Quote:

Regarding the air bleeds:

I have a similar setup as Bullit on my 340.

When I was using a 750cfm Proform main body on my double pumper It ran rich and throtle response was not as sharp as my 650dp. I called Quick Fuel Technologies and they suggested I change my Primary screw in air bleeds. Original bleeds were #75 outboard and #36 inboard, Sugested change is
#70 outboard and #30 inboard.
All secondary air bleeds are #36 (no sec. mixture screws.)no changes being made.
Coast is $4.00 per set. I am waiting for delivery.



Hi Tampacuda:

That would make perfect sense. Changing your main air bleeds from 36 to 30 will delay the start of the mains, essentially leaning out the bottom end. 30 is more in the neighborhood of what you'd expect to see after a Holley has been tuned on a mild street engine. 36 is rather largish.

Perhaps the Quickfuel folks thought that after you'd delayed the start of the mains, you'd need a richer idle to compensate, and hence the change of the idle bleeds from 75 to 70. If it was me, I'd swap the main air bleeds first and leave the 75's in the idle. If it doesn't exhibit lean symptoms, I'd stop there. If it does, you can always change the idle bleeds next.

It is generally agreed that the idle air bleeds should come in between 50 and 75, and if you need to go outside that range you probably need to look at something else. Bullit's problem is that he's already maxed out as far as idle air bleeds are concerned. He could possibly go larger but eventually he'll reach the point where additional air bleed size won't make any diference.

Bullit possibly has the same problem as you're working on - rich low end (including idle). Problem is, once the car is moving, you no longer smell the foul stench and assume everything is OK. Ignorance is bliss, eh?

Jim