I dont like the single line pumps. They dont allow you to run a vapor return line. I would check your fuel pressure, (it should be 5 or 6 psi or so, but most importantly, it shouldn't drop off a lot when you open the throttle) I've run a factory type (with the big canister) high volume pump with 3/8" outlet and a vapor return line for years on a 455 with no fuel starvation. Make sure that you also have 3/8" line coming from the tank, as well as the pickup. Some were only 5/16". I did run a Carter high volume pump without vapor return line before this and had vapor lock issues in hot weather. I think the Carter pump is a good unit, but running a return line seems to keep the fuel from picking up excess heat before entering the carburetor. Just some ideas, hope this helps.
