Well it cuts both ways I'm finding out. most bottom end stuff from 318 340 la engines fit. The intake and exhaust manifolds or headers are the issue. Chrysler Power makes a killer manifold but it's pricey and a waiting game. Also worth the wait from what I see and read. The heads need porting and this is where the price comes in but getting them ported and having your rocker gear reconditioned is, can be cheaper than buying good aluminum LA heads and the exhaust side will out flow most La heads ported by the right guy. Cams can be made to order or there are vendors that have profiles in stock.