HELP sbc 350 with holley carb hesitates on full throttle

[1985Chevycutlass]

every time I try to roast my tires a little, the car hesitates then accelerates. it makes a sound similar to a backfire but not as loud. it sounds like its coming from the carb. I have a sbc bored .30, an edelbrock performer intake, mild towing rv cam, and holley carb. dont know what model carb it is but i hope the pics help. can someone explain why its doing this please. i might just put a regular ol quadrajet on it. 😢 it does this everytime i put the pedal to the floor, from a complete stop and during driving. all advice welcome. here are some pics of my setup.

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[1985Chevycutlass]

 

[1985Chevycutlass]

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[1985Chevycutlass]

 

[gs dewd]

looks like a 600cfm holley. The power valve is probably toast. Any ideal of the age of the carb? It may need a rebuild. Also have you checked the float levels and make sure there not to high?

 

[1985Chevycutlass]

not sure, i bought the whole engine and transmission used with less than 2000 miles on it from a friend and had a mechanic drop it in for me.

 

[1985Chevycutlass]

I think i'll just snatch it off and install a qjet and hope this fixes the problem. since I have no idea the year of the motor, how do i know which qjetnto get. Jegs have 3 or 4 different ones

 

[chevypower86olds]

yep its a holley 600 list #1850 looks like, very popular carb . good for daily driver or good towing cam, not much for high horsepower. as you can see the front vent pipe is wet from gas overflowing from it some time or another (looks recent) mainly caused by trash in needle/seat . carb is missing choke linkage and bracket but will still run fine with a rebuild . pump could also be out of adjustment and yes a blowed power valve also . just needs a build. fixed many many of them , good carbs. holley rebuild kit part number is 37-119 , around 20 bucks at autozone , advance, or oreilly..usually in stock. the 80457 is a carb identical except it had electric choke. got 2 full 5 gallon bucket of parts to fit it if ya need any.

 

[XbeasleyX]

If you wanted to through a Q-jet on you'd need a new intake aswell. Unless there is square-bore quads.

 

[1985Chevycutlass]

thanx for all the help guys. just bought a brand new holley and did a complete tune-up and its still doing the same thing but its not backfiring anymore. when i drop it down to 1st gear and put the pedal to the floor the car cuts off. ANY MORE SUGGESTIONS GUYS :?: MAYBE WEAK FUEL PUMP? TIMING OFF?