Quote:
Originally Posted by gtome
This may all be a posibility?? All i can say is with my set up.
With my old HEI dist, changing from manifold to ported vac made absolutely no difference anywhere....even at idle. Put I knew it was problematic.
So I bought a new dist (HEI...thanks PDude!) and the ported vs man vac makes a big difference.
On the new dist, I put a hose to the vac can and sucked on it and I could hear it pull and snap back without a whole lot of effort. That is the extent of my testing.
I guess what i am saying is that I am making 14 hg of vac, on a brand new dist and can, and I do see a slight hesitation, with ported advance, before the advance comes in (but I dont know that it is vac advace...could be mechanical is coming in??). With manifold vac, it is very smooth and no noticeable transition. Is there a problem here??? Doesnt seem to be...but i couldnt say for sure.
By the way I am making 16* at idle with 36* in by 3000 rpm
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i would check for ease of movement of the vac advance with the cap off. if it pulls and releases easily, then it's good. also, if you have a can that pull alot of advance, it may take a little longer to get there, but not enough to notice. another thing to think about; vac advance is good for lean conditions. if you see a difference coming on the throttle between ported to manifold (after the can has checked good), you may just need more accelerator pump shot. so, a performance difference in manifold and ported may be an indicator of a needed carb adjustment. just another possibility. but i still believe covering up a vac can/pump shot problem by having to use fmv is not right. once everything is correct, then choose what works best. i'm not a 'only ported' guy, either. i run one of each!