1985 chevy 366 replaced with a 1984 454 out of an rv

[azratrod]

so my 1985 chevy 366 does have a thrown rod. ive been looking for a replacement 366 but havent had much luck. ive thought about rebuilding the one i have. but today i came across a 1984 chevy 454 thats still in the original rv and it only has 22,000 miles on it. the guy only wants $600. its a great price and saving me alot of money. but im worried this 454 motor wont be a direct replacment. im also wondering if the 454 will have enough power to move my short bus. the 454 is in a rv so it should be ok for power. but what about making it bolt in? arent the cooling hoses and thermostat different?

any help?

any suggestions?

any ideas?

thanks

[Stuff]

hmmm .. motor mounts might be different. look up the tranny and see if it will bolt up to your 454.

[bapos]

I know chevy motors in passenger car applications but the bus world is a new one to me... Knowing what I know the mounts may be diff but the 366 should move over to the 454 with direct swap? Those motors are from the same family. Lots of things interchange but NOT all parts.

As for if it would have enough power I would say yes. I think one of the biggest difference I have reading about is.... the 366 is in the tall deck family so it should have an extra ring on the pistions which the 454 will not. I dont think its a major difference but one that will be probably be shown as the motor ages and racks up miles.

I have a 366 in my 83 GMC Ward 66 passenger that doesnt have a 100k digit in the odometer so who knows how many times its rolled?

Let us know what you do I am wanting to get a ready to install motor on the engine stand so when that day comes for me I will have the back up ready to go.

Good luck!

Bapos

[Joe Monstermaker]

It will bolt in on the same mounts and it will bolt to the same transmission.
It is a low-deck motor, the intake manifold is smaller. The exhaust manifolds will bolt onto it but will have to move inward just slightly.
I'm not sure about whether the flywheel/flexplate balance is the same. I'd use the 454's original flexplate if possible.
The 454 isn't set up for cooling as well as the 366 is. I did once do the exact opposite swap, put a medium-truck 427 (similar to a 366) in place of a 454 and I've forgotten the exact layout of all the external accessories but I remember it being a real pain-in-the-butt to get everything together and working.
The higher deck height means the cylinder heads on your 366 are further up and apart from each other than the 454, so the accessory drive mounting holes end up out-of-place.
It can be done but there's going to be a lot of little issues to deal with before you ever get it running, it won't be a quick simple bolt-in-and-go.
Overall you will be better off finding a 366 or 427 or rebuilding your old 366 unless you're like me and tend to do everything the hard way.
20k or so miles is pretty low but remember that 454s in motorhomes tend to be about used up by 50 or 60k and your bus is probably a heavier load than the motorhome was. There's a reason medium trucks and busses never came with 454s.
Oh, and I'm assuming your bus does NOT have air brakes. If it does then note that the 454 does not have the provisions for mounting the compressor.

[opus]

There was a post here awhile ago about 366 vs 454. I would personally stick with the 366.

[lornaschinske]

I have a 454 in my Class C. The RV weighs about 2 tons. I get 6 to 8 mpg. But it's a good engine. I have gotten the Class C up to 80 mph on I 20... not the smoothest road. I don't think I could have stopped it too quickly but the motor seemed to like being pushed and I probably could have run it faster. Because of the stopping distance required (and the fuel sucking capabilities once I get into the back 2 barrels of the carb), I rarely put the Class C over 65 mph. But the short time of the faster run seemed to help the motor since it sits more than it runs ( a common occurrence with most RVs). I had gotten hung up in traffic getting back onto the interstate and had to run to catch up with David & Stacey. If you don't mind the poor MPGs and it will swap in, why not. Keep in mind, it probably has sat more than it has run.

[Joe Monstermaker]

Originally Posted by lornaschinske

I have a 454 in my Class C. The RV weighs about 2 tons.

That's 4000 pounds... About what a new Camaro weighs...

[lornaschinske]

It's definitely a heavy old thing. When my daughter first drove it, I told her it was like dancing with an elephant. You do things slowly and carefully. Move too fast and you can get squished!