wide open hesitation???

I fined tuned my carbs and everything is great except now when I put it to the floor it stumbles and when it picks up it dosen't feel it is pulling all that it should. I am thinking my rear jets might be to small or my power valve might need to come in sooner. I went up 2 sizes on the rear jets to see if that is going to help. Which would you say could be a problem?

I dont recall your build, can you tell us info on your set up . My best guess without any knowledge of your build is maybe fuel pressure or inadaquate supply of fuel . May need more pump ? just guessing

Needs more pump shot/squirter?

Its a 521 SCJ deal, 13:1 compression. Weiand T/R with 2 holley 750 Vac secondaries. I have 35 squirters, 70 jets in the front and 76 jets in the rear, I converted to a 4150 metering block so I can change jets. It has 50cc accelerator pumps. I am also running a brown pump cam. Right now it has 4.5 power valves. I put 78 jets in it this evening but it started to rain so tomorrow I will be able to tell if that was going to help any. I am running a holley HP 150 fuel pump with 1/2 line to a 4 port regulator with 3/8 line going to each bowl. Set at 8 psi. It seems it is starving but couldn't spend much time on it tonight.

Maybe it needs a 6.5 PV

maybe it needs no power valves in it.i had 2 600's on a 460 back in the day and it had that problem too.i always wanted the 660 center squirter carbs but never got them.

I have some 6.5 power valves In my drawer. I will get to them today. I have thought about pluging my power valve but it kinda seems it would only be idle or WOT capible.

I drove the car with the 78 jets, still hesitates, but the jets seem to work, going with the 6.5 power valve and see how that is. It still might need more jet, dunno we will see. Check back later.