port o sonic revisit

Well I got my heap back together, runs much better but now has a flat spot when I get on it, my question is with such a big plenum and the 4150 to 4500 adaptor would two 50cc pumps help this??

I have no details on your carb, but I would move larger on the squirter nozzle size first. When the nozzle size gets large enough to make the pump shot duration too short, then go to the 50cc pump.
If it is a big carb, it will probably like a big nozzle and pump. Lots of variables unknown..size and model of carb...type of booster...type and effectiveness of modifications...ect.
Keith

850 holley, standard boosters just has the choke horn removed.

A regular 850 Holley already comes with a 50 cc pump on the secondary side.

Start with a 37 shooter on the primary and a 40 on the secondary. If you go much larger than 42, you will probably need a hollow hold-down screw.

If it is strictly a drag racer, switch the pumps, levers and cams primary to secondary with the big one on the front.