Does any have any experience with the 400?

[78clubcab]

Hi, I am working on restoring my 78 clubcab with a factory 400/727 combo. The truck has 114,000 and I'm contemplating rebuilding it or at least gaskets, coreplugs, timing chain and gears. I guess I am a little wary of the 400 because I've never had one and have no experience with them. I.ve thought of swapping in a 318 because I've NEVER had a 318 I didn't love! I was thinking of building the 318 just like the one in my 73 Plymouth. I used "302" casting heads and put 1.88 valves, 9:1 comp pistons, edelbrock .420 cam, performer intake and 1406 carb with headers and 2 1/2 exhaust with x pipe. The truck has a 3.55 rear. I think a 318 would be fine. I know I would need a SB trans. Just wondering if anyone has any thoughts one the 400. I've had 360's before and they were nowhere as smooth or dependable as my 318's, but maybe that's just me. I guess I just like a 318 and if I am going to rebuild............... I don't know. Thoughts on the 400, anyone????

[Don Williams]

The 400 is a bored out 383 that was a "smog" engine of the 70's. A good solid engine but in completely stock form it suffers from the smog equipment of the 70's.

[78clubcab]

I am also thinking of an A518 conversion. I see an adapter kit for Big Block is available. Just tossing some ideas. I also heard from a friend at work today that a co-worker has a 78 Powerwagon that he purchased new. I am trying to find out more details, if it is for sale etc...

[USN78W150]

400 engine

The 400 is a great engine, but so is the 318. The 400 shares the same stroke as the 383, but has it's own block due to the large bore size. The 400 block has the highest nickel content of any Chrysler cylinder block, which makes it extremely durable. The only downside to it is the two barrel carburetor, which doesn't supply enough fuel for the engine to live up to it's potential. If you stay with the 400, use a factory iron 4 barrel intake and Thermoquad carburetor. The intake manifold is the only external part that is different between the 400 and 440 engines, so you will have to use a 383/400 specific intake. Good luck whichever engine you decide to go with, and keep us informed of your progress.

[712edf]

The intake manifold is the only external part that is different between the 400 and 440 engines,

440 uses a longer distributor shaft, but that's irrelevant to this situation since he has a complete 400. Good advice on intake!

Bucky

[Don Williams]

The 400 block has the highest nickel content of any Chrysler cylinder block, which makes it extremely durable.

This would help explain why the 400 block is such a popular candidate for building a stroker motor. I've always wondered about that.

[Gordon Maney]

The 400 is a great engine, but so is the 318. The 400 shares the same stroke as the 383, but has it's own block due to the large bore size. The 400 block has the highest nickel content of any Chrysler cylinder block, which makes it extremely durable. The only downside to it is the two barrel carburetor, which doesn't supply enough fuel for the engine to live up to it's potential. If you stay with the 400, use a factory iron 4 barrel intake and Thermoquad carburetor. The intake manifold is the only external part that is different between the 400 and 440 engines, so you will have to use a 383/400 specific intake. Good luck whichever engine you decide to go with, and keep us informed of your progress.

Interesting about the nickel. I wonder if that is true for the corresponding heads.

[USN78W150]

400 engine

The heads on the 400 are the same as those on the 440. Chrysler cylinder blocks have the highest nickel content of any maufacturer, and the 400 has the highest content within the Chrysler offerings.

[QuantumJo]

I'd keep the 400. Thats what I have in my 77 Adventurer.
http://www.powerwagonadvertiser.com/...reat+adventure

[greg rider]

The '78 that I owned years ago came with a 400/727 combo. I had problems with it blowing head gaskets. I had the block and heads checked and even one time had the machine shop assemble the heads to the block, no luck. The 400 is a 383 bored out .092". I finally went with a 440 and never had problems with that till it broke the oil pickup tube years later. If you are considering a rebuild you may not be able to bore too much more without getting the water jacket too thin.

[USN78W150]

400

The '78 that I owned years ago came with a 400/727 combo. I had problems with it blowing head gaskets. I had the block and heads checked and even one time had the machine shop assemble the heads to the block, no luck. The 400 is a 383 bored out .092". I finally went with a 440 and never had problems with that till it broke the oil pickup tube years later. If you are considering a rebuild you may not be able to bore too much more without getting the water jacket too thin.

The 400 has it's own block casting, and is not a bored out 383.

[QuantumJo]

Mine is .030 over, I was told that I could go .060 if I had to.

[greg rider]

The 400 has it's own block casting, and is not a bored out 383.

Thanks, I was unaware of that. The only thing I knew was the specs on it and the only difference I picked up on was the bore. It used the same stroke as a 383 but with a larger bore. I was told that the cylinder walls were thin and close to the water jacket. This is why they couldn't be bored too much.

[712edf]

Thanks, I was unaware of that. The only thing I knew was the specs on it and the only difference I picked up on was the bore. It used the same stroke as a 383 but with a larger bore. I was told that the cylinder walls were thin and close to the water jacket. This is why they couldn't be bored too much.

That was a common misconception that even Mopar literature of the era supported.

www.440source.com

Read about blocks & casting numbers.

Bucky

[tinner12002]

adapter

Hey clubcab, I have an adapter as you mentioned for using a 46RH OD trans on a big block if you decide to go that route, brand new never used for $350. I would reccomend a pre 96 trans as it only has 3 computer wires to control the OD and converter lockup, very simple to hook up manually.