Don Terrill’s Speed-Talk

having problems with a 950.first off its on a 8.2 deck 363 13.1 comp vic jr heads,super vic intake,fti solid roller nitrous grind 260sint,280s exh 689 699 109 int center 112 ls. redneck c4 an 4500 converter.eng pulls around 5psi vaccume at idle. it has a 2.5 pv,pink cams on both primary and secondary,primary blades are open just enough to square transfer slot. has 35 squirters frt and back. jets are 78primary and 85 secondary.car starts and runs fine but when footbraked to 2500-3000,it boggs and dies,no pop just like someone shut it off.car doesent move.stall it up hit the trans brakeand 2 step mash it and it takes off.is it just too lean at part throttle? secondarys need jetted up?
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power valve closing?

vaccuum would climb on the footbrake but on the 2 step the throttles are wide open?

I would test without the pv and see if it goes away (obviously increasing main jet to compensate)

Yes jet it up as that's too lean for your combo.

Start with 80/88 and go up two sizes at a time front and back.

Increase the the PV size to a 3.5"

It doesn't look too lean for the carb size, your engine will tell you if you read the plugs whether it's lean for your engine or not. I have two questions, what plugs do you run (brand and part #) and what is your timing and curve, or locked? Also, I'd run a 3.5 - 4.5 PV, may not be an issue but you don't want it too low. If the engine vacuum goes up high enough at higher RPM it can close and run the engine lean, a bad thing.