butterfly effect

I just fitted a zz383 gm performance engine. The carb that I used is a holly double pumper 4150 series pn 0-82751 , 750 . What jets and power valve should I start with? I also used their single plane intake.

WWK888

You are in the wrong section, this is Help for problems with the forum, like posting pics etc...

BlackRocket

I have the same problem....383 with a Barry Grand 750 Mighty Demon. I know the engine is running rich so I will just get one of those jet kits from Summit or Jegs and start installing smaller ones until it runs right!

babbah

WWK888

Why are you rolling your eyes at me? When the op first posted this it was in the Help section (like in help with posting pictures etc...).

Obviously a mod moved this thread to the proper section after my suggestion.

Curveit

Carb jetting is usually pretty close. Make changes 2 steps(jet sizes) at a time; 1 step probably wouldn't show enough difference to evaluate. After you figure if you need to go richer or smaller, you can fine tune to 1 jet size.

gkull

Normally out of the box most carbs are somewhat close for a moderate engine at sea level. The holley web site just like the Demon web site has the base line settings.

the ZZ383 and a single plane would probably use a 6.5 PV. single planes need an instant squirter. So set the squirters for instant action.