i have been trying to tune my carb, its been getting better everytime i do something to it...

i have a 750 holley dp on a mildly built 350. i think the carb is to big for the engine, but i havent had the money to buy a smaller one yet. the engine is finally broke in, so yesterday i thought i would do a few WOT runs....the engine really likes to rev, and it pulls extremly hard until 6,000 rpm, but when i start slowing down, and get back down around 1500 rpm's or so, the car stalls. i can smell gas after a WOT run, so i assume that the engine runs extremly rich at high rpm's.

how do i tune the carb so it doesnt stall anymore?
also, it seems like there should be more power when the secondaries open...do i have to change a spring or something?

 

A 750 Double Pumper is definitely too much CARB for a mildly built 350. It'll run decent, and sure, it'll run rich.... but it shouldn't be stalling though!

Did you over look anything? Is the power brake vacuum line leaky.... or not hooked up? It sounds like vacuum, cuz if it were that rich, it wouldn't rev like that at all without the infamous 'spark knock' associated with either a lean or rich condition.

I would pick up a quadrajet (just for the mean time), out of any junkyard for peanuts.... and give it a good cleaning with solvent, and a new accelerator pump. Use this for now.... until you save up for a vacuum secondary 650 CARB...

My 2 cents anyways

 

If you hit the brakes hard & slow down really fast, then it dies, you might have a fuel float problem. They could be set too high.
Is your ignition & timing all in order already?

 

The above also applies if you make a right or left turn (especially after braking), and the engine starts to stumble.... then dies. The float is probably set too high if this be the case, especially if it's a 750 Double Pumper on a 350 SBC.

 

Trade you your 750DP for my 650DP.

Although you probably just have a float problem. Could be the setting of the level, or excessive pressure that is exhibiting itself at higher RPMs.

Don't get a VS carb. You'll just kick yourself if you do. If your engine pulls to 6000 RPMs and doesn't bog when you nail it, you should be fine with the 750DP (although I'd be better off with your 750...).