Old School vs Magnum on 86 Dodge W100

Well, I would mill .030" off of the LA318 heads to get down to the same chamber size and keep the compression ratio advantage of the Magnum.

But....LA318 heads will be a shaft rocker system... that will be the problem.... no oiling passages up through the Magnum block to oil the shaft rocker setup. Almost sounds like the reman magnum heads are the way to go. Maybe check out the present Magnum pistons for ring skirt diameter and groove wear, and, if good, put them back in after a hone in the block, to save $$ for heads. Sometimes you gotta compromise....

OK, on the cam. That makes life easier since you are not going with a hi-po build. But it all sounds up in the air now.