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440roadrunner · 11-12-2007, 11:08 AM

This is just my opinion, but unless you are going to rebuild the engine, I'd stay away from Motorhome engines. They are under a LOT more stress, burned valves, etc. If you plan to rebuild it, and it's cheap, I'd say no problem.

If you are in a rebuild situation, and your 400 heads are in better shape, you can use them. If you need your 400 pan and oil pickup, it will fit the 440. If you have very low miles on your 400 cam (I don't know what you've done to it) such things as the cam drive and cam/lifters will fit. Most all external parts, water pump, brackets, etc, should fit.

The engines should be a bolt in but......

The intake and distributer will NOT interchange from 400 to 440. The 361/383/400 is a short stroke "low deck height" motor, so the push rods, distributor, and intake are different.

The 413,426, and 440 are long stroke (raised block or RB) and so have longer pushrods and distributor, and wider intake.

Anything else, headers, mounts, etc should be a bolt in

EXCEPT:

Here's where I'm unfamiliar. 400's MAY BE externally balanced, I'm not sure. I'm also not sure if any of the motor home 440's are or are not externally balanced. I do NOT know how Chrysler did the balancing. The extra weights may be on the flex plate, or the converter. In the case of a stick, you need the special flywheel. You need to check this out.

Even my old '70 six pack 440 was externally balanced, as opposed to the 383's and 375hp (4bbl) 440's which were not externally balanced.

11-12-2007, 11:08 AM	#2 (permalink)
440roadrunner Senior Member Join Date: Nov 2007 Posts: 272	This is just my opinion, but unless you are going to rebuild the engine, I'd stay away from Motorhome engines. They are under a LOT more stress, burned valves, etc. If you plan to rebuild it, and it's cheap, I'd say no problem. If you are in a rebuild situation, and your 400 heads are in better shape, you can use them. If you need your 400 pan and oil pickup, it will fit the 440. If you have very low miles on your 400 cam (I don't know what you've done to it) such things as the cam drive and cam/lifters will fit. Most all external parts, water pump, brackets, etc, should fit. The engines should be a bolt in but...... The intake and distributer will NOT interchange from 400 to 440. The 361/383/400 is a short stroke "low deck height" motor, so the push rods, distributor, and intake are different. The 413,426, and 440 are long stroke (raised block or RB) and so have longer pushrods and distributor, and wider intake. Anything else, headers, mounts, etc should be a bolt in EXCEPT: Here's where I'm unfamiliar. 400's MAY BE externally balanced, I'm not sure. I'm also not sure if any of the motor home 440's are or are not externally balanced. I do NOT know how Chrysler did the balancing. The extra weights may be on the flex plate, or the converter. In the case of a stick, you need the special flywheel. You need to check this out. Even my old '70 six pack 440 was externally balanced, as opposed to the 383's and 375hp (4bbl) 440's which were not externally balanced.