I've done a ton of research- so now I'm really confused....

Murray said

The combustion chambers are the same size and your 302 heads will flow less air which means less power.

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Exactly. The 302's are a nice replacement head for any 273 or 318 but they are not a cure all. Even the guys that bolted them on a 340 or 360, what small gain you may get with the closed chambers you will loose with the smaller ports.