Which Engine? Which Intake?
Pull an intake bolt out and see if it's a 5/16 or 3/8. 5/16 were used on the 64-65 heads. Truth is.....either intake will work on the wrong heads it wasn't designed for. I ran the D4B intake in the pic below on a 71 318 in a Challenger for several years with no problems. Pic below shows that same D4B sitting on the 273 that I just built and it has 302 heads on it with the later bolt angle. I tightened the bolt in the pic down just until the washer touched on the bottom. The gap at the top is how much of an angle washer is needed for it to be done properly, instead of the tighten and hope method I used years ago....lol. If you have 64-65 heads and duplicate the pic above using the LD4B, the gap will be at the bottom instead of the top.
Pull an intake bolt out and see if it's a 5/16 or 3/8. 5/16 were used on the 64-65 heads. Truth is.....either intake will work on the wrong heads it wasn't designed for. I ran the D4B intake in the pic below on a 71 318 in a Challenger for several years with no problems. Pic below shows that same D4B sitting on the 273 that I just built and it has 302 heads on it with the later bolt angle. I tightened the bolt in the pic down just until the washer touched on the bottom. The gap at the top is how much of an angle washer is needed for it to be done properly, instead of the tighten and hope method I used years ago....lol. If you have 64-65 heads and duplicate the pic above using the LD4B, the gap will be at the bottom instead of the top.