340 timing question

[AR67GTX]

Only if your cam is mild enough to pull enough vac at idle to pull the can in. I have a motor that idles at 8" vac and hooking it to manifold vac won't work.

Not sure about the mopar sources but I have a 427 Vette with a 256/[email protected] .600 lift cam that on a good day pulls 8 inches of vacuum advance. I have a vacuum advance unit on the old TI distributor that is a stock unit for old mech lifter engines that starts to activate at about 6 inches of vacuum. I got it from NAPA. I would think something similar is available for Mopar distributors. I did have to fab a limiter on it to stop it at 8 degrees because with the 12:1 pistons and aluminum open chamber heads I was getting too much advance at cruise on the highway and it was lightly kicking back. The Chevy crowd has a whole table of GM vacuum advance units produced over the years and where they start from and how much total advance they pull in. Maybe there is something similar for Mopars.

 

[Bill Monk]

Only if your cam is mild enough to pull enough vac at idle to pull the can in. I have a motor that idles at 8" vac and hooking it to manifold vac won't work.

Yeah, that's a different animal. Most wouldn't use a vacuum advance at all with that kind of set up.

 

[JG1966]

Can anyone ID this distributor? Can't find any markings. I read how to adjust mechanical advance on a MP/Mallory distributor but not sure if this is one. If not, how would I go about lower mechanical advance? Thanks

 

[beanhead]

I'm not sure exactly which one you have, but it's not the newer adjustable style...you'd have to perform the old weld-and-file surgery--best bet is to get you one of these...http://www.manciniracing.com/fbomodilipl.html
Since you already have it opened up, not much more work to use the limiter plate....plus much cheaper than a whole new distributor.