Originally Posted by lewtot184
Originally Posted by Mopar493
Originally Posted by lewtot184
[quote=Mopar493][quote=lewtot184][quote=Mopar493][quote=lewtot184i know Don at FBO likes full manifold vacuum for the vacuum advance, I don't; unless the vacuum is so low you need the extra advance at low rpm. I wouldn't do that with as high of vacuum as your engine is making. I bet that engine is making a bunch of low to mid rpm cylinder pressure with that cam closing the intake valve so early and this could lead to some detonation. don't be afraid to try the timed port. those vacuum units are adjustable.

Yes he told me to use it, i did a compression test and it shows 200 psi on all 8,i test in 4 pulses on every cylinder and the gauge swings up to 150 psi on the first pulse. The cam close the intake valve 64 degrees after BDC so its pretty mild for the cui's. I have not heard any pinging so far or not seen any signs of it on the piston tops but i have only drive it with the msd pro billet distributor set at 16 initial and full advance at 3000rpm and 34 degrees, so i dont know yet how it respond to vacuum advance, i have to test it some and see
it's not rocket science just be patient and don't put your head in a box. 200psi is high for pump gas so you may have to walk a fine line to stay out of detonation. I use the mopar distributors in both my cars and I do mimic mopars centrifugal curve set-ups for street along with the vacuum advance. I went thru a bunch of different configurations to come up with something I liked.

Thanks for your answer