[tdangle]

Originally Posted by burnin oil

Whats the base timing at idle? That is not a big cam at all and should have no vacuum issues. I have 250 duration cam in my truck and still have vacuum brakes that work. It sounds like you need a recurve of the distributer. I would hook the vac gauge back up and twist it to you get a good vac reading then limit the advance to the 32 degrees you want overall. Once the curve is set you can play with the vac advance if you like. I dont have it hooked up on my truck and milage is horrible. 7.5mpg on a good tank! I am willing to bet that it will run better with vacuum advance when the curve is set up correctly and gain a little mpg as well. I would not listen to GM here unless it is a track only vehicle. They are not always correct.

I agree, it doesn't seem like a big cam. It has a LSA of 108 (LCA of 107 and 109), so even thou it's not a long duration cam it has more overlap than you would realize making it seem like a bigger cam as far as the idle goes. I've learned way more about cams than I care to know at this point. I'm going to raise the initial and work on limiting total advance to see it that makes it better.