I think the general consensus is you can use the 64 aluminum head/intake setup on a 65 or later 300, but you have to use both. Not just the intake. Someone with more knowledge of the 300 will be along soon I imagine.
check my for sell ad post 8 will answer youre question http://www.v8buick.com/showthread.php?t=160000 wkillgs I did the swap on my '66 300. The 64 intake will fit a 65-up head, but the 64 has a smaller port size than the later heads. I opened up the manifold port at the flange so they are nearly the same size as the iron head. I don't recall which intake gasket I used, but only one of them would work. The iron heads use exhaust gas to heat the manifold, the alum heads use water. There is an exhaust passage that needs to be blocked off when using the alum intake. It will work with some mods. But you still have smaller intake runners than if you used the 65 iron 4bbl intake. side not...smaller runners mean more low end torque correct
