273 4 barrel intake 64

Stock cast 65 4 barrel manifold is casting number# 2465726. (no 4 barrel 273's in 64) Edelbrock made a D4B which is aluminum and harder to find than the stock cast manifold. The 64 and 65 273's had a smaller attaching bolt and at a different angle than the 66 on up small block manifolds. The newer manifold bolt holes can be modified to work if you choose.

Any small block manifold will fit. All 66 and newer manifolds will have to be modified. Ones specifically made for the 273/318 will have the correct port size.

By the way, Welcome to FABO. Love your 64. I was looking for one when I found my 66 15 years ago.