On the non-Magnum (pre-93) engines I would always select the 360. The pre-Magnum 318s didn't have enough power and spend most of their time straining against the load. My Dad has had both 318 and 360 powered B-series vans, the 360 consistantly got 2-3 more MPG than the 318s. Stage V heads are the key to this engines power and versatility. If you are not familiar with the Stage V heads, they are the highest quality, most accurate machined head for the 426 Hemi with significantly improved stock style ports. Modeled after the 1965 Race Hemi, the intake port is much larger than todays reconfigured Mopar Performance head.
Jul 30, 2009 · What heads were most commonly used. I have 8418915A 2.02 IN & 1.60 EX The heads & Block was done by R&R machine. The valves were way too deep, but the better part is the seats are out of round, leaks.. I didn’t find out until I pressure tested the engine after installing the heads. 1978-1979 Puch GN, Maxi, Maxi Luxe, Sport, Newport L, Sport MkII, Maxi II, Magnum XK, Magnum MkII