The cars up until like 1962 had the extended crankshaft, both 318 Poly and big block-that is with the cast iron trans. The early 318 and early big block will both bolt up to the Poly trans with the correct bellhousing. The cast iron trans bolted up to the bellhousing just like a manual trans. I would probably use a drivetrain from a post '62 vehicle. You have to decide if you want to keep the original trans-it would make the swap easier. They had a completely different kickdown setup and the throttle rod pushed on the bottom of the throttle lever on the carburetor. Then the brake system, if power-used the weird bellows booster with the master cylinder mounted directly underneath the booster. The industrial 440's used that extended crankshaft, I have a nice one if you need it.. I helped a friend put a 392 Hemi in his 58 Plymouth. It bolted directly to the Poly 318 transmission. There are a couple You Tube videos of this car after it got sold a couple times if interested. I'll find them.. Then you have the tapered keyed rear axle. A 68-70 B body rear axle will fit about right. PM me for more info.