If that is a 74-76 carb then I would say that it isn't calibrated for your higher horsepower set-up. Things that I think Cliff Ruggles would suggest would be to #1 buy his book (probably the best $20 you will have spent in a while, #2 check float level, #3 fuel inlet seat size, #4 choke pull-off function, secondary air flap adjustment. If the carb needs a rebuild anyway, I would buy the book, get a kit of good parts from Cliff, and do it yourself. I did mine myself for my built 400 (400 horse est.) and 4 speed with a junk '79 Q-jet I bought for $20 on ebay. You can give Cliff the parameters of your engine and he can pretty much recommend jets, rods, secondary rods, etc. For instance, I was talking to him on the phone about ordering a new set of rods and main jets for my new motor and when he found out it was a '79 he suggested that I send him my secondary rods so he could mill them down to significantly richen up my secondaries, otherwise he thought the lean rods could melt the pistons. He knows his stuff and if you get him on the phone have your info ready and some time on your hands because he likes to talk! My car is a little scarey fast now (but I did have a tired 326 and an auto) Good Luck.