thsorens

So I put a 383 stroker in my old 23 foot WebbCraft last fall. I put the stock quadrajet intake and carb back on, and it ran fine, but the carb was always hard starting, so I pulled it over the winter and rebuilt it and epoxyied the well plugs. It starts up great now, but I developed a new problem. At first, I could run WOT (4800RPM) for about 100 yards, then it just ran out of gas and fell back to 3000rpm or worse, until I let the carb fill back up at idle and hit it again. I replaced the fuel pump, still had the problem, took the fuel tank pickup out, and it has a 1 way check valve in it which I blew out. It took care of the problem, sort of. Yesterday, I was running WOT for about 3 miles, and it gradually started dropping off, til it was running about 4000 RPM at WOT. Either I screwed something up when I rebuilt the carb, or that 1 way valve needs to go. Another boating buddy/mechanic friend of mine said he always chucks those 1 way check valves, because he has had problems with them in the past. Any ideas? The only thing in the carb that was slightly questionable, was the accelerator pump they gave me in the Mercruiser rebuild kit, was shorter than the one that was in it. I checked the number against 3 or 4 different sources, and decided I had the right one, and the original one must have been wrong. It accelerates fine, its just prolonged WOT situations that are giving me grief.
Thanks in advance!
Tom