Setting up my Cliff built quadrajet

[69giant]

I got my 17080213 installed that cliff built. I have 100 miles on it and its running good. My mostly stock 350 in my 72 Chevy truck. The carb has no ported vacuum port, I tested both with gauge while idleing, they are full manifold. My question is how are my timing settings. 12 initial with a 10 degree limit on the vacuum advance on my new GM performance ZZ HEI . So I have 22 at idle. I am looking for good gas mileage. Thanks

[77cruiser]

If it runs great like that perfect. I use manifold vacuum most of the time. How much vac. at idle?

[69giant]

The vacuum is 19 at idle.

[Cliff Ruggles]

Using manifold vacuum to the advance at idle can work on some engines, as long as you can get them to idle down with the idle speed screws.  I've seen very mild engines where a lot of initial timing makes them idle too fast no matter what you do.

Fuel economy really isn't effected by using a ported vs manifold source to the vacuum advance, for "normal" driving both will be doing the same thing at light part throttle.  Manifold vacuum does add timing when coasting where ported does not........Cliff