413 MOPAR advice please

Pull the valve covers and check the head numbers and post them here.

Some heads listing in the book as a "motorhome head" are actually passenger car heads, i think the number is 242 or something. they are almost identical to the 906. Very few winnebagos and other motorhomes had the true industrial heads, with the extra cooling ports and odd exhaust. Likely, your motor has passenger car heads.

The 70's 413 was an industrial block, with extra gussets, ribs and other strength enhancing modifications to the early and then-current passenger car blocks. This extra stuff added about 10 pounds to the weight of the block. These are the best block to start with when building a 600+ HP motor.

If you are going to build it for some power, I recomend 452 or 906 heads, with 2.14 1.81 valves. There are a few pistons available for a standard bore 426, which that 413 can be bored to without any trouble. That motor will have a forged crank, which will be just fine for any build. David

 

Another thing that I don't think was mentioned - that 413's crankshaft flange is most likely different than your 440. The industrial and truck engines have eight instead of six bolts attaching the flywheel, and the 8-bolt flange sticks out further from the block than the 6-bolt version. Moral of the story: keep it with its trans if you decide to run it.