F4Gary said: They are in carburetors. Mostly Holley.
the power valve works in combination with vacuum, to richen the fuel supply to the carb under heavy load, the number stamped on the power valve tells you when it opens, my 750 has a 65 which opens at 6.5 Hg of vaccuum. 5 months ago I suggested that you go back to portd vacuum rather than direct vac, I assume your MSD dist. has a vacuum adv. canister on it, did you try it, and if so what happen, I'am friggen pissed because this afternoon I spent about 45minutes explaining why you don't use direct vac to the canister and when i Clicked on the post button it went to never never land, think about it, if you put 12 degrees of initial into the motor and plug you canister into direct vac. and the canister has lets say 12 crank degs. of total advance built in it you now have 24 degrees of initial at idle, right? wrong! static means it doesn't move, because the advance canister varies advance with throttle position and vaccum at low to mid range your initial is moving around causing either a surge or stumble, I'll say it again, plug it into ported vac. just like factory, holley, edelbrock suggest and forget the BS on how cool, and good they run with direct vac. and let me know.
|UPDATED|9/29/2012 6:07:44 PM (AZT)|/UPDATED|