The Conversion of my 86 Crown Supercoach

[flattracker]

Thanks for the offer of the lights. It would be tempting to put white lamps in these for those who refuse to dim their lights at night (for some reason there are a lot of Oregoners that won't) but I think they would be too high to put much light on the road. I plan to replace the front directionals with an extra set of headlights (an actual Crown option for coaches) and add new directional signals to the front bumper. I think if I can use LEDs in all the headlights, the extra lights will not tax the circuit for the headlights. The other day I was at the bus and noticed that part of my taillights had rusted through. I have spares though.

[Crown_Guy]

Originally Posted by flattracker

Thanks for the offer of the lights. It would be tempting to put white lamps in these for those who refuse to dim their lights at night (for some reason there are a lot of Oregoners that won't) but I think they would be too high to put much light on the road. I plan to replace the front directionals with an extra set of headlights (an actual Crown option for coaches) and add new directional signals to the front bumper. I think if I can use LEDs in all the headlights, the extra lights will not tax the circuit for the headlights. The other day I was at the bus and noticed that part of my taillights had rusted through. I have spares though.

Actually the Crown standard was with quad headlights and high mounted turn signals until about 1971 or so when they changed and started using the lower headlight housing for turn signals. Cheaper to do than the extra step of popping a hole in the panels to accept the turn signal buckets. The early Crowns usually had the smaller sealed beam amber PAR lamps, with some custom builds having the larger styles with the non-sealed beam lenses over a socket lamp underneath as they are today. Check the internet for Crowns and you'll find all kinds of cool varieties. I drove for Embree back in the day and they had the high mounted turn signals in the special cast housing sometimes called "bug eyes" and the Crown quad headlight standard setup. I love this look and will be converting mine eventually to have this. I've attached a few sample pics for reference and I point out the #32 which is to me the classic Embree look and what I will be doing to mine. These housings are pretty much unobtanium and only available if you get lucky in a scrapyard or someone lets you have them. They were not very common at all and very low numbers were ever used except for those rare customers who also liked them and ordered them special.

I've also attached a found pic of Embree #63 in almost authentic livery and still in excellent driveable condition owned privately. #63 is displaying the very typical look for that time era of the amber sealed beam turn signals below the windshield. As it happens I drove the hell out of #63 when it was in service and took it places a Jeep would think twice about, and those quad lights came in REAL handy. Each headight had low and high beams, and the second pair were turned on with the "Auxiliary" switch on the dash. So on really dark roads you had all four headlights capable of putting out High Beams for that little extra that came in so handy. This was the standard at the time and now, boy do I miss it with the pathetic single pair of headlights mounted today, which I have trouble driving beyond what they safely illuminate.

The high mounted sealed beam turn signals were standard until about the same 1971 time frame when Crown went to the twin headlights and low mounted turn signals we see today. #63 was built in 1963 and that was the prevailing look. I think Embree pioneered the high mounted casting bug-eye custom look and started ordering theirs with that in the late 1960's. I may be wrong but once the castings were available Embree ordered all theirs with that feature.

As to using the crossing light housing for driving lights I'd suggest you consider it not for lighting the road but to light up the countryside ahead and any trees or other potential problems. My goal will be to use them as general Landing Light type illuminators to show the lay of the land approaching and get prepared. This is very good to have on those inky dark roads where you only see whats in your headlight beams. I've experienced this at times and wished for super long range terrain illuminating lights to give me some advance notice of what I'm approaching and if I really want to go there. In case you're worried about the amperage being required by the headlights, and any extra driving lights, remember you can always pull in heavier wires to the lamps and install a relay powered by the dash switch. This isn't hard and the benefits of getting full voltage to the lamps makes it worthwhile, as well as not burning up the switch contacts and dash wiring....

Extra lights are never a bad thing. Since you already have the housings pointing in the right direction you might as well find a good use for them. I know I will. You can also find the metal flip down covers around that will cover the lens and allow for flipping 90 degrees up to become the hood when you want to use the lights. The rears should probably have this to cover any clear/white lights pointing to the rear which is usually illegal in most States. Up front not so much unless they don't allow for high intensity off-road driving lights being uncovered. We used the flip-downs all the time when we shifted from school bus mode to Charter bus mode and could then haul-ass at more than 55mph, which all Embree Crowns could easily do 70 for highway cruising.

You have many options as a private owner and I'd encourage you to take advantage of the many ways you can tailor your Crown to your needs and get the most out of it. Don't worry about the concept of "stock" or "original equipment". There wasn't any such thing since Crown custom spec'd and built to each customers requests. There was a base line of installed equipment and some districts used that as pure cost cutting, but most added on and changed as they saw fit which is how the wonderful varieties of Crowns you see around was made possible. This is also why you can still find parts to repair or upgrade your Crown and keep it on the road. It's mostly just run of the mill off the shelf heavy duty truck parts. You can customize as you see fit and make it truly your own, with a clear conscience. Have fun.

[flattracker]

Thanks to Crown_Guy for the excellent pictures. Over the years I was able to acquire the headlight bucket parts and will enjoy the extra lighting. I think four headlights give the Crown that extra pizazz in the front. I will have the unique striping across the front but it will be red instead of black, as the bus will be white with red. All this with the chrome badging in the front put the nose of a Crown over the top. The new Crown still has the badging but the old one had it missing. I understand that folks that worked at the bus yards were fond of keeping those. I once visited the bus yard in San Jose Ca. and they had the skins from the front of a crown mounted to the wall.

[Crown_Guy]

Originally Posted by flattracker

Thanks to Crown_Guy for the excellent pictures. Over the years I was able to acquire the headlight bucket parts and will enjoy the extra lighting. I think four headlights give the Crown that extra pizazz in the front. I will have the unique striping across the front but it will be red instead of black, as the bus will be white with red. All this with the chrome badging in the front put the nose of a Crown over the top. The new Crown still has the badging but the old one had it missing. I understand that folks that worked at the bus yards were fond of keeping those. I once visited the bus yard in San Jose Ca. and they had the skins from the front of a crown mounted to the wall.

Just like big game hunters. Trophies...... They loved their Crowns too and HATED having to get rid of them. I've talked to lots of mechanics and Firemen who still wish they had their Crowns and Firecoaches back and not the junk being pushed off on them today. Every Crown I've seen lately has had the badges thieved, usually by the shops at the districts before they left, sometimes by cannibal metal thieves when parked in accessible places or on the streets. I'd STRONGLY advise all who own Crowns and still have their Crown emblems to remove them for safe keeping, and then when ready re-attached with stainless steel pop rivets to discourage thievery. The regular screws are just too much temptation to easily remove them. You may notice my avatar and they are gone from my Crown. But I took them off and have them stored safely away until I'm ready to put them back on permanently over a new paint job. All cleaned up and restored to their original glory. They are truly becoming unobtanium and worth protecting at all costs.

[flattracker]

I came across some images of the "old Crown" that I thought I would post for fellow Crown aficionados. The location vary. from near Big Sur to the Salt Flats, the Sierras.

[Crown_Guy]

Originally Posted by flattracker

I came across some images of the "old Crown" that I thought I would post for fellow Crown aficionados. The location vary. from near Big Sur to the Salt Flats, the Sierras.

Please forgive my confusion here. But do you still own both of them? I understand the "Old Crown" versus the "New Crown" but still seem to miss the "Both Crowns"?? I have the Cummins Tandem and now also a Detroit 35ft 2-axle Crown as well. I intend keeping both for different reasons and absolutely had to have a Detroit 10 spd for the pure fun factor and driving enjoyment. Plus the getting back to my roots thing. I was born in a 5 spd Detroit Crown when I learned to drive commercially, and that never leaves you.

Even though they are almost the same in handling and maneuverability due to the superior design and engineering of Crown, I do find the 2-axle slightly easier to handle in Really tight confines. I intend to use it more for the adventurous camp(s) and nasty road explorations into the unknowns I hope to embark on, much as I did all those years ago in commercial service. I know what it will do and feel confident that if I can drive into a situation I can drive out successfully again.

The Tandem is only just slightly less nimble and makes me work harder to get in and out of tight spots. Not anything like any coach where I usually had to walk and see if I could even attempt it, I've made passengers walk more than once if I felt I couldn't get in or out, even if it was a simple driveway situation.

The Tandem isn't anywhere near that bad, but it does demand some respect for its length and rear end tail slap. The 35ft feels and acts like a Jeep to me and I've really taken them into truly scary spots, and back again.

The Tandem is massively powerful and the OD 10 spd RoadRanger coupled with the Cummins going to 2400 or so rpm gives a truly awesome road-speed. I've had it going a clocked 85+ and it was going higher with no end in sight. My experience in coaches and other high speed Crowns I've driven through the years has made me quite conformable at cruising at about 74 mph on the road, with the concern being for the front tires and the loads they carry on the coaches the only limiting factor. The Tandem isn't carrying anything like those loads so I'm very comfortable going as fast as it will go, with a clear conscience, weather and speed limits permitting of course. But if you've never experienced the open interstates where the Trucks are blowing you off the road as you're going 70 or so you'll understand my reasons for speed. Plus the Crown handles superbly at high speeds so you don't really even feel it much at all, better than most coaches really.

For me this makes it my choice for long distance highway adventures and the Cummins is quieter and less frantic on the highway compared to the Detroit Song of the Road. I love them both and they do have different missions that they are each very good at individually.

Sorry. Don't know how I got off on this. Bored I guess, being cooped up with nothing open, and all I can do is drive around the area to keep the batteries up and fluids circulated, but in a Crown that's reason enough. I got them mainly to DRIVE them, that's 90% of the reason. Have a Happy New Year all.

[flattracker]

Hello Crown_Guy. Yes I still have both Crowns. The old crown is parked in my yard. I ended up storing some of my stuff inside it at the end of our move from California. It developed a radiator leak, and eventually I will get that repaired. I did enjoy taking the "old Crown on trips, but didn't care for the lack of power, and that is why I bought the "new Crown".

[Crown_Guy]

Originally Posted by flattracker

Hello Crown_Guy. Yes I still have both Crowns. The old crown is parked in my yard. I ended up storing some of my stuff inside it at the end of our move from California. It developed a radiator leak, and eventually I will get that repaired. I did enjoy taking the "old Crown on trips, but didn't care for the lack of power, and that is why I bought the "new Crown".

Storing stuff in my Crown......Shoot, I thought I was the only one that ever did that. Too tempting really and since I don't have anyplace else to keep all the stuff I've accumulated for converting it, it ends up in the Crown. At least it's all right there for when I do manage to get some work done on it, but 50 miles away puts a real damper on that unfortunately, and the dirt lot, and no services like electricity, water, lighting, or compressed air. Makes doing the simplest of things a real challenge.

Ahhh yes. Let me guess, non-turbo naturally aspirated 6-71. They were the only thing going for many years, and all we knew, until the late 1970's when they finally perfected how to engineer and fit the turbo into the Crowns.

It was a serious engineering challenge and took some time, but once it was done, most all Crowns were ordered with the turbo and the naturally-aspirated ones faded away. Today when I drive one I'm reminded of just how spoiled we've become with the very powerful new generations of engines. The non-turbo 6-71 will ALWAYS get you there and back, but it may take a while...... As the altitude increases they lose power and start putting out more continuous black smoke, due to lack of oxygen and running too rich. We just put up with this and thought nothing of it until of course we had a taste of the new engines and turbo-charging. What a difference.

The real difference showed up in the highway coaches when they started fitting Detroit Diesel Series 60's in them. The difference from driving any of the various 2-stroke Detroits 6 or 8V92 or 8V-71's in common coach use compared to the Series 60 was shocking to say the least. There was so much torque they pushed that bus like it was a car, literally. We could keep up with traffic and accelerate with them, even on the hills we didn't lose speed much at all, and they never got hot like the old 2-strokes always did since we were working them so hard. It made many drivers lazy what with the automatics and never ending power they tend to lose touch with the fine points of driving and knowing about their vehicle. You see this today in the commercial drivers I've interviewed to drive the nice old (1974) 6-71 naturally-aspirated Crown 5-spd I still drive in service. Very few can handle it and even shift gears. Sad to say it's becoming a lost art.

You've become spoiled by that Cummins and all it brings to the table. I know that feeling due to the Cummins I have as well. That's why I made a point of getting a second Crown with a 6-71T and 10spd for the power, as well as the fun factor. Best of both worlds as far as I'm concerned. I intend to travel with them a lot and altitude performance is a big deal with the 6-71. I experienced what the turbo could do on a ferry trip to Boulder CO. The engine continued to perform as it did at sea level with no smoke or loss of power, Boy was I sold. I was convinced to only buy a 6-71 turbo when I got a chance for my long distance and high altitude trips. I found one and snagged it recently and am very happy with it's potential.

[flattracker]

My "old Crown" has the turbo with the Allison automatic. I do like the Cummins setup though.
The "old Crown" did get 10 mpg.

[Crown_Guy]

Originally Posted by flattracker

My "old Crown" has the turbo with the Allison automatic. I do like the Cummins setup though.
The "old Crown" did get 10 mpg.

Well that sounds like a real solid setup. Turbo 6-71 with an Allison. And you didn't think it had enough power?? That's exactly what I drove to Boulder and it was Great! on the road. Could there have been a problem? Or maybe small injectors and the thing set for fuel pinching and low power due to the District wanting it that way?? I've seen this before and folks think the engine is bad or can't be fixed. I've seen many here in Kalifornia with the various styles of damned throttle delay and fuel schedulers installed to reduce smoking but all they do is make them almost un-driveable around town with lots of starts and stops. Once wound up and on the road, not so bad, but in all cases they sounded like they were being stifled and reminded me of what old style Transit Buses with 2-strokes were like with a pathetic excuse for any exhaust roar. Penny pinching, and everything being done to reduce the engine to barely being able to move the bus around. Some may think this is normal and how they were all set up to run.

That's not true and you can do many things to get the engine to put out lots of power and make it run real strong on the highway and in the hills. Detroits can be souped up a lot and made to perform well beyond the standard Fleet units we see in Districts and penny pinching operations. As a private owner you can do things to make it run and snarl like a beast and still get good mileage and long endurance. That's what I plan on doing with my 6-71T. Turn it into a monster fit for an owner-operator who demands the best performance possible and knows how to drive it to make it last.

Detroit for a few years were doing things with their cam shaft timings and attempting to clean up the engines. All it did was make them run like s**t. I've been told that for a few years in the mid '80's they all came with this. I don't know for sure the exact years but I can find out. I'd be interested to know what year your Crown was made and if it might have had one of these Kalifornia Smog Krap engines installed, even though it obviously was going to WA or OR with those lights and side crash rails. If so there may be things you can do to improve the engine performance substantially so you can enjoy driving it around.

The Detroit 6-71T Crown I now have is an '82 and potentially in this range of crap cams as well, but I've been reassured that it was re-powered by the friend I bought it from, who operates a charter company and I can trust his word on that. So, until I start digging into it myself, I won't know exactly what I have, but I know that with enough money I can turn it into the monster I want it to be. It's all doable. Just takes money. The 6-71 blocks are all the same. It drives just fine as it is, so it may be an OK setup, but I do want the most I can get out of it, a real snarling hot rod. That's just me.

[flattracker]

The "old Crown" is a 1981 model from Washington State. I had discussed making it go faster with a race buddy that is a diesel mechanic, working at a truck repair shop in Salinas, where they worked on Crowns and actually re-powered some under a state program. They did all the engineering to make it work. He had told me that any effort to make the Detroit faster would shorten its lifespan. I will say that I did not have any significant problems with the bus. How slow it was on climbs was mostly a factor of how steep the climb. On Hwy 17 going from Los Gatos to Santa Cruz the bus was in first gear going up the climb. First gear has a max speed of 18 mph. The new Crown has not drove Hwy 17 yet so I don't know how it would be, but I believe now with the gearing changes it would likely be 3rd gear, 50 mph (the speed limit on that stretch). The "old Crown" was upgraded to 24" tires which helps. When I am finished with the work to the "new Crown" I plan to fix all that's wrong with the old Crown and probably sell it, as I don't need two Crowns. One smart move I made some years back, was acquiring spares for the Detroit from the truck shop in Salinas, as they had Detroits to be destroyed for the state (from the re-powered Crowns). I ended up with a compressor, alternator, fuel pump, and starter.

[flattracker]

A side note:
I have an original Detroit Diesel series 71 service manual sections 4 - 15. If someone wanted a copy, I could take it to staples and have it copied. Whatever it cost me at staples would be what I would have to charge for it. They usually do a good job at Staples. I haven't found sections 1 - 4 yet. I don't yet know if there is sections 16 - x. Producing a digital copy (PDF) would be a large task.

[Crown_Guy]

Is the new Crown also an Allison auto? If not what's it got in it.

If road speed were your biggest concern on the old Crown a relatively simple change of the rear-end ratio would have given you all the speed you'd need. Hill performance would usually be expected to suffer too but you don't get anything for free. We changed the rear-end from the standard 4.10 to 3.90 for that Crown I drove to Boulder and I found it was superb on the highway cruising very comfortably in the engine sweet spot at around 2100rpm at 74 mph. It topped out at a solid 80mph on the governor, GPS verified. We took Wolf Creek Pass Eastbound in 3rd gear, pulling fine until it got hot, which is normal and to be expected at low rpms, then 2nd gear (Allison MT647 4spd auto) sitting very comfortably on the governor the rest of the way up the grade at about 30mph, quite respectable and better than I expected with that new rear-end ratio. Excellent overall performance actually. Great on the flats and great on hills.

30mph is the normal speed up most grades and corresponds to the manual 5spd third gear, (out of the five), which is again typical second gear for a coach's 4spds. Back in the day we always went up hills at around 30mph and that was the way it was, no matter what we were driving, or the engine it had in it. It's only lately with the monster Series 60's in the coaches that everyone expects to fly up hills with the cars, and not even get the engine hot. Spoiled is the word I'd use.

I still suspect you have a deep down engine tuning, smog equipment, overall camshaft design, and or a simple non-advanced cam timing going on in that engine to give such anemic overall low power performance. Something doesn't smell right. The 6-71T should put out about 270HP with something over 850ft lbs of torque. If it's not tuned correctly or tied down by previous fleet operators to get better fuel economy I'd not be surprised at it's current performance. Something funny going on.

Actually I just had a random thought as I typed this and it might bear checking out. It might be a simple matter of the mechanical throttle linkage not actually moving the governor fuel lever to fuel full position where you get the best power. The Detroit Crown I recently acquired actually has this exact problem, and it's something I'll be dealing with later. I can feel it as I drive, but I have enough experience to know how it's Supposed to feel, where anyone without previous experience in these engines may not be able to tell the difference or feel that it's wrong.

On the Allison automatics, not with a manual transmission like mine, there is a transmission kick-down linkage attached to the throttle linkage at the governor with some springs and such. These all have to be adjusted so that the pedal is demanding, and the governor is reaching the full fuel position, while still not pulling on the kick-down linkage. I saw one recently where it was all messed up and the throttle pedal and engine governor fuel position was being overridden and prevented from reaching full fuel by the mal-adjusted kick-down linkage.

All the symptoms you describe make me think the engine isn't actually able to reach full fuel with the throttle pedal. There are also a couple of spots in the pedal linkages itself where adjustments can be made to ensure a full and complete stroke so you get all the travel needed at the governor fuel lever for full fuel. This is essentially a fairly simple matter of checking and properly adjusting the pedal linkages and then making sure the kick-down isn't impeding it, but it's still operating enough to signal the transmission when it's engaged by a hard stomp on the throttle pedal. Tricky and a little Zen like to get it right, but that's what a good mechanic is all about. Without understanding what's supposed to be happening they'll never get it right. I've seen this for myself.

This isn't uncommon at all after all the years of many different so called mechanics diddling around on your Crown. Very few understand the inter-related dynamics or take the time to make sure everything works as it should......assuming they even know what that is.

Good luck and I hope it's something simple like this that will restore your faith in the Crown and that 6-71T Allison transmission combo. They should run like the devil is after them when all is working correctly.

[flattracker]

I don't know if this is the right place to post this but I discovered an eBay listing for a 1960 Crown bus this morning. It looks to be a project but the current bid is $105.50.
The bus is located in Burney Ca. No reserve, 3 days left.
For someone who needs a low priced starting point bus, it looks promising. Just passing the word.

[rossvtaylor]

Originally Posted by flattracker

I don't know if this is the right place to post this but I discovered an eBay listing for a 1960 Crown bus this morning. It looks to be a project but the current bid is $105.50.
The bus is located in Burney Ca. No reserve, 3 days left.
For someone who needs a low priced starting point bus, it looks promising. Just passing the word.

I saw that last night...and if it weren't almost to the Oregon border in California (too far to tow to Flagstaff) I'd take that on. The body's pretty straight. He says there's such high oil pressure that it blows the filter off after running for about 30 seconds. It's got new oil lines and he "removed and cleaned" the oil pressure regulator, but it's still an issue. I don't know that particular engine at all, but in other engines this might indicate spun main bearings that block oil passages. Or not? If I thought there was a decent chance I could get it running to drive home, I'd risk it. He does say he'll allow work to be done on his property. But, not knowing that engine at all, I've reluctantly got to pass on this... which makes me sad!



BTW, did you see my PM to you a couple weeks ago? I'd be interested in "Old Crown" if you decide to sell her... she'd fit right in next to Gillie, our 74 Gillig.

[flattracker]

We had to drive to Bend (Oregon) today and on the way back I stopped and took some pictures of this unusual Crown coach. It kind of resembles a sound van that Crown made for Universal Studios back in the day. It is parked off Hwy 97 south of Chemult on the west side of the highway. Based on the size of the windshield I think it was made 1950s - early 60s.

Anybody know more?

[Crown_Guy]

Originally Posted by flattracker

We had to drive to Bend (Oregon) today and on the way back I stopped and took some pictures of this unusual Crown coach. It kind of resembles a sound van that Crown made for Universal Studios back in the day. It is parked off Hwy 97 south of Chemult on the west side of the highway. Based on the size of the windshield I think it was made 1950s - early 60s.

Anybody know more?

More likely a HiPo (Highway Post Office). US Postal Service used them for a while to sort and bag mail where there wasn't convenient railroad or airports between cities. They'd drive them all night with a crew in the back sorting and getting ready for arrival at a mail center in the morning. Like you say that's a 1950's era vehicle and they made enough of them up into the early 1960's that they still show up occasionally.

They also used that basic box shaped body structure to good advantage for other custom applications as needed for Television production studios. KTLA here in L.A. had a few of them for many years and used them on remote location events like parades, and sports venues. Pretty much before the nice, and much smaller, RF enabled stuff used today. They had to carry literally tons of cables, plus the cameras, and a full-on studio production and switching facility were housed in the Crowns to manage the camera feeds and switching between them in real time. The transmitting and up-linking was also housed in another Crown, and generators, don't forget the generators, all in all a mammoth amount of equipment to handle the simplest of remote events. It was a hell of a feat at the time.

Red Skelton also had a couple he used for his own productions. They were easily converted and used for cargoes with rear doors if needed, but usually they were better used as production studios and location equipment storage vehicles.

They were built back when the the Hall-Scott gas engines were king and later ones were powered with the Cummins 220 non-turbo diesels. All mid-mounted pancake engines in the standard Crown configuration. If you can find one that's not been left to rot and in decent shape overall you could make a real decent RV out of it, if it's a Diesel.

In fact there's been more than one shown up on some of the Crown picture's sites I've noticed. Lots of room under the raised floor to add goodies as well as work on the engine and running gear. This one's a 1966 and it has the tall windshield. Unknown to me who, what, or where but I found it online.

[flattracker]

I don't know the condition of this Crown, but I first saw it last year in the same spot. Would it be difficult to put a modern Cummins Big Cam in one? Maybe with an Allison automatic?

[Crown_Guy]

Originally Posted by flattracker

I don't know the condition of this Crown, but I first saw it last year in the same spot. Would it be difficult to put a modern Cummins Big Cam in one? Maybe with an Allison automatic?

It's doable but certainly not a minor job. And the engine has to be modified to lay down too. Many issues that Crown did and made it look easy, but it's not really. Real question is if the overall vehicle is worth the expenditure of all that capital and effort. There are still some fine Crowns around with original Cummins/Allison installations ready to go and very driveable. It's got to be in really good condition to make it worthwhile when, and if, you finish the re-power process.

[flattracker]

Originally Posted by Crown_Guy

It's doable but certainly not a minor job. And the engine has to be modified to lay down too. Many issues that Crown did and made it look easy, but it's not really. Real question is if the overall vehicle is worth the expenditure of all that capital and effort. There are still some fine Crowns around with original Cummins/Allison installations ready to go and very driveable. It's got to be in really good condition to make it worthwhile when, and if, you finish the re-power process.

Thanks for the input. One really has to start with a Cummins already from a Crown, since the oil pan, oil pump, oil pump pickup,compressor, and bell housing are special to a Crown. The rest of the engine is the same as what came in OTR trucks. The replacement engine in my "new Crown" came out of a Peterbuilt. When researching the issue of re-powering mine after the main bearing failure, the Cummins parts book listed only one engine block, but two oil pans, one being the type used in Crowns. I know that later they replaced the cast oil pan with a stamped steel one so technically there are three different oil pans used in the Cummins. The other issue may be in the differential, since with 4.10 gearing one runs out of RPMs at 63 mph. (at least for a Cummins)