Hello f-100352,Blown Burb here. I don't know if you noticed what I have been up too with my sons 71 El Camino, but it has a 750 dual feed sqarebore carb on it. One of the things I found out was that this carb is only supposed to be getting 7.5lbs. of maximum fuel pressure. You may want to be sure there is not too much fuel pressure that could unseat the needle and seat assemblies. This information came from the Holley Tech line and I wouldn,t think that a 650 cfm carb. would need more fuel pressure than a larger carb. Good luck and I hope this helps.