[RocktimusPryme]

Originally Posted by Cliff R

Anyhow, what I recommend when it comes to this topic is to make absolutely sure that your distributor adds NOTHING below about 900-1000 RPM's with the mechanical advance, nice smooth curve all in around 2800-3200rpm's or so, and about 10-14 degrees from the VA. Set the initial timing so the total timing isn't going to pound the rod bearings out of it, then start testing manifold and ported VA sources to see how the engine responds. Some engines will enjoy 20 degrees or so timing at idle, others will not. Another thing that deal can get you on is that adding a bunch of timing at idle requires that you lower the idle speed screw and nearly close the throttle plates.

I bolded that one section because I think that is likely my combos issues with full manifold. My cannister adds the better part of 20*. I know that is an issue. So my RPM in park jumped 500 RPM when I switched vacuum ports. At 1500 RPM I was seeing like 35*, probably some mechanical advance and all the vacuum advance. When I lowered the idle back down to 900ish I was seeing 30* on the crank, which is what I would expect given I know my initial is about 12*.

But because I had to back the idle screw off so much it likely had the throttle plate issue you described.


I remember in another thread you mentioned that there was a good one size fits most starting point as a measurement between the vacuum advance arm and a physical stop. But I cant find it. I think it was .120? Or something like between .110 and .150? Can you refresh our memories there?

One other oddball note, it seemed to me that the RPM drop from park to gear was greater when I had it on the full manifold. I get a little drop normally but its pretty tame. 100 RPM give or take. It was probably 250 or a little more on the full manifold. It actually died on me the first time I put it in drive.