To start off I have a 340 bored and honed to .30 over. RPM performer alum. heads, crower cam with 495 lift @ 240 duration and 112 lope sep. Everything ported and polished. Mighty demon 750 carb.

So I had the Dart 340 dynode last night and I was running rich. Like after each run we had to leave the shop because of the exhaust. So the shop guy said to get it down. Started with 75/83 (pri/sec) and he said to go down 3 on the pri. and 2 on the secondary. So I put in 72/81 and went for a drive. Just driving it seems fine but when you hit the gas at like 2500-3000 rpm the car falls on its face and then goes. So I put the original 83 back in the sec. Now the car doesn't fall on its face but still hick-ups upon full throttle.

So my question is WTF. I feel like 72/83 is too big a gap for the right jetting. I am in Hawaii (so sea level). but i need some help.

 

Here read this carefully. You need to learn Holleys because they require lots of care and feeding. You are trying to cover an accelerator pump stumble with main jets, that will make your tuning problems worst.

http://www.bob2000.com/carb.htm

There are you tube vids that will help a little, but not much. Learning carburetors is the only way to tune them.

 

You have a Demon Carb that works!!!!..............Cause mine out of the box didn't!!!! and still dont work! Guess why they are out of business!!!!!