Just remember, the 64 and 65 273 heads use their own intake. (smaller bolt holes (5/16" instead of 3/8") And the bolt angle is different. 66 and newer small block heads are different and "normal" Stock 4 barrel intakes for the weird early heads were 65 only. Performance intakes are hard to find. Offenhauser and Edelbrock (D4B) made them. You can hog out the bolt holes and use some weird wedge shaped washers, but that's kind of crude really.