1966 GMC Short School Bus questions

Gazolba · 10-08-2016, 01:30 PM

I'm looking at a 1966 GMC bus. Owner says it has a V6 Chevy engine that is locked up. What engine might that be and would it still be repairable? Or what type of replacement engine would swap in? The bus has a Superior 24-pass body. Is that a good body? I like the size of this bus (21 feet long). But wondering what problems confront me in having such an old bus and where I could park it. My HOA prohibits such vehicles. Lastly, the bus is still yellow which is illegal in my state, how do you paint a bus? Can I just brush-paint it. Thanks.

EastCoastCB · 10-08-2016, 01:46 PM

Quote:

Originally Posted by Gazolba

I'm looking at a 1966 GMC bus. Owner says it has a V6 Chevy engine that is locked up. What engine might that be and would it still be repairable? Or what type of replacement engine would swap in? The bus has a Superior 24-pass body. Is that a good body? I like the size of this bus (21 feet long). But wondering what problems confront me in having such an old bus and where I could park it. My HOA prohibits such vehicles. Lastly, the bus is still yellow which is illegal in my state, how do you paint a bus? Can I just brush-paint it. Thanks.

Most of us are dealing with much newer machines.
Lots of the buses of that era had six cylinder gas engines. My buddy has a 66 Ford with an inline six. Also locked up. He uses it as a storage shed... We got it free from an OLD hippie.
The problems you'll run into are the same you'd run into restoring an old car. Everything rubber is usually GONE, every aspect has to be addressed, and lots of rust repair and bodywork.

cadillackid · 10-08-2016, 02:58 PM

superiors liked to rust badly... superior went out of business in 1981 so parts are near impossible..

a locked motor.. anybody's guess if the block is destroyed or not.. often a locked engine is due to a spun main bering which destroys the bearing cavity in the block..

if its a chevy engone and a chevy bolt pattern you might be able to drop a 350 or a 454 in it.. alot of times the frame had the holes for the motor mounts for other engines already drilled.. if it was a nonstandard bolt pattern then the trans will be hard to mate to a new engine..

most HOA's dont like busses or RV's and have written rules against it.. I rent storage spots for mine and that worls out well... not sure how you would fair with an HOA and trying to swap a new engine into it..

most states prohibit yellow but im not reading of any people in this forum getting stopped for a yellow bus before they get it painted.. and some people's busses are yellow for a long time..

-Christopher

Carytowncat · 10-08-2016, 03:19 PM

For the price of the engine repairs a good running bus could easily be found.

Good luck!

cadillackid · 10-08-2016, 03:38 PM

unless he is like me and seems to always have engines on stands built and ready in the garage with nothing to run them in lol

-Christopher

Carytowncat · 10-08-2016, 04:55 PM

Quote:

Originally Posted by cadillackid

unless he is like me and seems to always have engines on stands built and ready in the garage with nothing to run them in lol

-Christopher

Again; It's a Wonderful Life

Brad_SwiftFur · 10-08-2016, 08:05 PM

Quote:

Originally Posted by Gazolba

I'm looking at a 1966 GMC bus. Owner says it has a V6 Chevy engine that is locked up. What engine might that be and would it still be repairable? Or what type of replacement engine would swap in? The bus has a Superior 24-pass body. Is that a good body? I like the size of this bus (21 feet long). But wondering what problems confront me in having such an old bus and where I could park it. My HOA prohibits such vehicles. Lastly, the bus is still yellow which is illegal in my state, how do you paint a bus? Can I just brush-paint it. Thanks.

That's *Probably* the old 305 V6 engine (or one of it's brothers). Not one of GM's best engines, and these days, darn near impossible to find parts for. Sure, parts exist, but if/when you break down in the middle of nowhere, you'll be on the roadside for a few days awaiting parts. That said, it is my understanding any of the usual V8 engines will bolt right in its place. You can consider a typical 350 or one of the truck/bus 366 engines.

I won't get into your HOA issues, as far as paint, sure, it's not uncommon to brush paint a bus.

cadillackid · 10-08-2016, 08:53 PM

an RV-Cammed 350 will run that bus right dwn the road.. keep in mind though you wither need to trust and buy a used one, buy a crate motoe or build one... and an intake and a carb, distributor.. have exhaust made for it etc..

its likely not a cheap endeavor..
-Christopher

cowlitzcoach · 10-09-2016, 02:33 AM

I would agree it most likely is the big block 60* V-6 from GMC.

If it is, it will have the spark plugs in the valley between the intake runners. They came in 305, 351, 379, 401, and 478 cubic inches. The 304 was usually found in GMC light duty trucks with the larger ones going into medium duty trucks and buses.

The diesel version of this engine was known as the Toroflow. The only difference was instead of spark plugs, distributor, and a carb it had injectors and a Bosch distributor style injection pump. As bad as the gas engines were, the diesel version was even worse.

If it is one of those engines take it out and use it as an anchor.

On their best day they never could get balanced correctly and would shake themselves to pieces. They tended to run hot so cooling was an issue. They were designed with the V in order to get good high end HP of a V-8 and a long stroke to get good low end torque like an I-6. Unfortunately it didn't have either. The power band was extremely narrow. Running it faster really didn't get you going faster but it did make a lot more noise doing it. Lugging it down very far and it would just quit. On the downhill you had to watch your manifold vacuum or you risked the chance of sucking out the head gaskets. To top it all off it was a very thirsty engine.

A perfect swap candidate would be a Tonawanda 366 high deck big block GM truck engine. The 454 would not be a good candidate for a swap. A small block on paper looks really good but in a bus it just doesn't have enough torque and HP. It is sort of like the difference between a 5.9L/ISB and an 8.3L/ISC--not a big difference on paper but a huge difference out on the road.

cadillackid · 10-09-2016, 08:24 AM

im thinking a 350 would handle that little 24 PASS superior fairly well.. finding a 366 in good shape these days and getting parts for it seems pricey... if it were a full size us id definitely not run a 350 in it.. but a shortie (5 or 6 row) superior id run an RV cammed 350 all day...
-Christopher

Brad_SwiftFur · 10-09-2016, 11:29 AM

Quote:

Originally Posted by cadillackid

im thinking a 350 would handle that little 24 PASS superior fairly well.. finding a 366 in good shape these days and getting parts for it seems pricey... if it were a full size us id definitely not run a 350 in it.. but a shortie (5 or 6 row) superior id run an RV cammed 350 all day...
-Christopher

Mind you, GM still builds a version of the 366 to this day - the 6L engine commonly available in pickups (not sure if it's the same block, but it's my understanding it is).

cadillackid · 10-09-2016, 11:49 AM

I thought the 6.0 was built on the same technology as the Vortecs...

4.8 / 5.3 / 6.0 .. arent those all aluminum or are they iron block?

I just think for a short bus theres more expense and effort involved in trying to build and install a towanda style truck block than there is in just dropping a 350 in and being done... you'll get 150,000 miles out of a 350 easily which is probably more than this bus will see in 20 years unless they plan to run the wheels off of it..

-Christopher

cowlitzcoach · 10-09-2016, 07:25 PM

I have driven smaller buses with the small block.

Empty they were not bad. Put any passengers on board and they had no go.

Granted they had carbs and points instead of EFI and HEI which really helps drivability. But at the end of the day, they are still small blocks.

In regards to new engines, I think the 8.1L is the closest relative to the Tonawonda high head big block engines.

cadillackid · 10-09-2016, 07:36 PM

I know a small block isnt ideal... was just trying to think how to get the OP on the roasd the simplest..

I dont know what Block the 454 I had in my original bluebird was... obviously end of the day it was a big block vs a small block.. i did a mild build on it but never touch the bottom end so i have no idea what the bore and stroke was on it...

cam, intake, lifters, headers and such for a regular 454 all fit it...

I know in a 5 window bluebird it screamed after i did a few bolt ons

-Christopher

Kubla · 10-09-2016, 10:14 PM

I owned a 61 ford b600 bus a long time ago, 292 v8, had adequate power and torque. The stock carb on it was a 350 holley 2 barrel, every gas powered medium truck I ran into during my truck driving career had a 2 barrel carb so if you stay with a gas engine, use a 2 barrel carb, you will save gas and your engine will last longer

cadillackid · 10-10-2016, 07:21 AM

Quote:

Originally Posted by Kubla

I owned a 61 ford b600 bus a long time ago, 292 v8, had adequate power and torque. The stock carb on it was a 350 holley 2 barrel, every gas powered medium truck I ran into during my truck driving career had a 2 barrel carb so if you stay with a gas engine, use a 2 barrel carb, you will save gas and your engine will last longer

if you spend a lot of time learning your driving habits you can tune a 4 barrell to be more efficient than a 2, and still have the extra Power when you need it.. Holley excluded.. I worked and worked to get a holley be efficient but its tough..

edelbrock I could tune down to a science that would run nicely... most of the big truck motors came with only 2 bbl as they were brute engines in which 2 large barrels are needed for good Low-end torque.. a 4 barrel fails miserably at the low end..

if runnign a bus with an AT545, a 4 barrel is perfect because the TQC stall speed is much higher thus allowing a V-8, even a smaller block to run up into its power band of RPM's when pushed..

I believe thats why AT545's never really were preferred in diesels because the stall speed runs up too high past the maximum torque of the motor..

-Christopher

Howard Hepburn · 10-10-2016, 01:19 PM

As said by others, this is a GMC V-6 not a chevy V-8 Thirsty heavy slugs, throw it away!

Just a thought, it would be far cheaper to find a modern wreck and transplant a newer GM LS engine. 4.8,5.3,6.0 or 6.2 they have far more power and reliability. The transmission is a lock-up 4 speed overdrive. Look for a 2wd pickup or G van. The salvage yards are full of them now. Do not be afraid of the fuel injection. Conversions are easy.

Gazolba · 10-10-2016, 07:09 PM

Thanks for all the information guys. I found a site which has lots of parts (body and engine) for this bus. It's called Classicparts.com. They even have disk brake conversions and rebuilt carbs. I think the way to go is to get the problem with the current engine diagnosed first before contemplating an engine swap. I looked on some GMC VIN decoding sites and could not decipher its VIN 3505 F10612D. I found a few VINs starting with '2505' but none of them ended in 'D'. I think this bus may be a 1965 registered in 1966.

cadillackid · 10-10-2016, 07:21 PM

its common for the chassis to be built a year before the bus... if you happen to hit near a model year break it very well may have been a 1965 chassi and a 66 body... im not sure how that was handled that long ago..

I know when I looked up the components on my latest bus its chassis was built in spring 1999 including its engine.. and the bus was sold as a 2000.. my VIN chases down correctly however things may have been different long ago.. they may have used the chassis year code and not updated it for a later model bus..
-Christopher

Brad_SwiftFur · 10-10-2016, 08:51 PM

Honestly, if I had a vintage bus (regardless of make), I would be highly tempted to drop in a more modern engine and transmission. For a smaller bus, I'd snag a fuel injected/TBI small block GM like a 350 ... for a larger bus I'd consider a 5.9 Cummins or DT466 (if there was room for it). If I had plenty of room, I'd even move up to a larger diesel engine such as an L10 or M11 Cummins with a 10-speed behind it. At that point, I'd be considering axle swaps and air brake conversions ...

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