Magnum heads on a 74' 318 LA
You need to talk to RustyRatRod, he's built one...
I have the engine, but haven't gotten around to putting in my car yet.
Magnum heads oil through the pushrods, so you will need the appropriate lifters and pushrods. They also have 1.6 to 1 rocker arm ratio. I think they typically out flow all of the older heads, save for ones that have the 2.02 intake valves. Bigger intake valve than all but the earlier 340 heads (1.92" vs 1.88" for later 340 and all 360, 1.78" stock 318).Valves should be lighter, too as they run 8mm stems, .315" vs .375". Drawback... Don't have shaft mounted rockers...
There was a thread on here of the build, though I couldn't find it last time I looked. Maybe he can give you the link.
The engine he built was to be low budget, but make good power.
Basically a totally fresh, blueprinted .030" over 318 bottom end, magnum heads shaved to give a true 9.2 to 1 compression running a Lunati 60403 cam, appropriate lifters/pushrods and valve springs. Edelbrock RPM Air-Gap intake.
He ran numbers on his dyno program for 650cfm carb and 1-5/8" headers and showed something like 330HP around 6000RPM, 350Lb torque.
I just haven't had the money lately to purchase a proper torque converter so I can get this thing done...
Oh, and WHY can I not type 3 1 8 without spaces and NOT get that damn emoticon... Yes my 3 1 8's make me smile smile but WTF?