Carb tuning

[justcruisin]

I am trying to tune my carb to run better at idle. 440 10.1:1 eddy heads rpm manifold   1 7/8" headers 830MS quick fuel comp xe275hl. I will get a LM1 or similar to help but I don't have one yet. Timing is at 20 initial + 15 mech, no vac adv. I have between 10-11" vacuum at 900rpm at the moment but the carb is clearly rich. I have drilled the IAB's from 70 to 78 and have been able to get some adjustment on the idle screws but I need to have them in to 1/2 a turn out for it to run OK. I opened up the secondary throtle to have about .030" of transfer slot showing. The primary has more but not sure how much as I have adjusted it a bit. Fuel is half way up the sight with 5 psi at the carb. Not sure which way to go from here, should I go to a smaller Idle feed. Any help appreciated.

[Chryco Psycho]

you may want to drill the throttle plates to get more air in without raising the idle speed & uncovering the tranfer slot

[justcruisin]

OK,what is a good rule of thumb for throttle position for both primary and secondary? How much transfer slot should be exposed on both?

[elacruze]

you may want to drill the throttle plates to get more air in without raising the idle speed & uncovering the tranfer slot

If you're open into the transfer slots, you don't have enough air at idle. You should be able to adjust idle below the slots, even if in the rare case you have to drill the butterflies. Perhaps the easiest way to get on the right track is to call Don Gould at FBO systems. www.4secondsflat.com