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Discussion Starter · #1 ·
Recently I took my 73 nova up to the drag strip. The car has a 412 Small Block Chevy. It has a 292 Comp Cam, 3k stall torque convertor, 750 vacuum secondary holley with a 4.5 power valve, hi rise intake, no air cleaner, th 400 transmission.
My problem is when i made a few passes the car would take off and immediately stumble. It only seemed to stumble when the car had been running, because it didn't stumble after the car cooled down. Yet it stumbled the next pass after that. I can not stall the converter because we could not hold the car still with front brakes. (I am putting rear brakes on now). My question is what could be causing the motor to stumble when it takes off? Thanks
 

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Discussion Starter · #4 ·
The Cam is a 292H-10. We followed all the guide lines from comp cams with a 3000+ stall and 10:1 compresion. We have 3.73 gears in the rear end too. The fuel system is a holley electric fuel pump and a reg. that is set at 6 psi.

The Holley web site also suggests the accelerator pump as a possible cause. How would I adjust this or know if this is the problem? Thanks.
 

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Discussion Starter · #10 ·
these all sound like possible fixes. The only thing that has me dumb founded is that of the 9 passes we made that day, 4 were fine no stumble, 3 had hard stumbles and 2 had a little stumble on launch. It seemed to run without a stumble when the car sat for an hour or so and cooled off. If the Stumble on launch was consistently there, i would be able to try things out.
The previous week before that we had a cross breed tire for street/strip on the car and on launch it would spin the tires for about 10 ft. and then they hooked up. The reason I mention this is because it didn't stumble once in 4 runs. A though i had is that with the slicks on and the 3k stall torque converter, the car launched and as soon as the converter locked up, it would bog the motor down until it could recover? What is anyone's thoughts on this. I am going to try to do some of the easy suggestions, but i really don't want to spend money on buying something till i know it will work. Thanks for your help guys!
 

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Discussion Starter · #11 ·
I have also read in holley's carb book that I should change the shooter size to a bigger one with the set up we have. I know someone mentioned this before. If it was the shooters wouldn't it stumble all the time? As you can tell I dont know everything so I am looking to you guys for help.
 
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