The specs on the original B7A-C cam are .447" lift (intake and exhaust) and about 290 degrees of advertised duration (intake and exhaust).
So 15" of vacuum at idle sounds logical to me.
The "C" cam is the optional cam for the dual quad and blower engines. So a lot more radical than the factory installed dual quad and blower cam (B7A-B).
Pretty sure the B7A-B cam is the same one in the 312 single 4 barrel engine too (245 HP).

    Sal

Sorry, I thought you meant each set was at 35. Your 33-36 total should be good.

Just an after thought but I had a Mallory dual point at one time and the engine started missing, after isolating one set of points it smoothed right out, never found out why that happened or what was wrong with the second set of points..

Jim thanks for post, been too long since I worked on a dual point distributor, need to go back and check these. The spec says 0.014-.016 gap and both are to be set same. The total dwell, both points should be 33-36 degrees. There is no dwell spec for primary point set, at least in documentation that I have.

I may be off base here but 35 on each set seem high. I've only run factory dual points on my FE and set at 28 each and then the total comes out about 32. Too much dwell may not be letting the coil build up enough and causing a week spark?

Could be rotor phasing is off in the distributor, I've heard talk that people fabricate the dual point breaker plates from the stock single point ones. That could be pretty tricky to do that accurately. I would check it dynamically using a timing light with the hole in the cap method.

Issue is not compression, cylinders read, 130, 132, 135, 135, 140, 133, 130, 135 in order 1-8. With the blower heads the compression should be 120-130.

I only know of the factory distributors. The tubing in your picture running from front of carb to distributor with the large loop is correct.

"The distributor used with blower does use a vacuum advance together with centrifugal advance."

... hmmpf ...

Interesting. So it uses a H4000 with a 57 dual advance distributor? Is the advance signal ported or manifold vacuum?



Did any F-CODE variation use only a mechanical advance distributor (HOLLEY - MALLORY)?  Was there a STREET VERSION and a RACE VERSION?      

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The distributor used with blower does use a vacuum advance together with centrifugal advance.

That cam has a slight lope and with my combo, (naturally aspirated) doesn't start to perform until about 1800rpm.  So idle to 1800rpm (mostly closer to idle speed) it does "misfire" but that's just the nature of the beast - it's how cams tend to work as they get bigger.  This is more pronounced when the vacuum advance is not used, which I think is the case with a supercharged engine, is that right?  Make sure you're not confusing something like that as a problem.


Lawrenceville, GA