Out of all the A-body manifolds what pn's are the best flowing? I would assume it is the late 340 ones but not sure. I was looking at them on ebay, and boy they sure look identical to my 73' 318 ones. They will be going in a 65 dart. Just figure the later ones must be better than the earlier 273 ones I have on there now. I was looking at headers but decided to stick with manifolds. Thanks!!