[Formulajones]

Originally Posted by i82much

I have the stock MSD Ready to Run canister hooked to manifold vacuum. It pulls 15" or so at the current idle speed and the idle speed drops noticeably if you disconnect it. The engine does not ping at light throttle so I can't see a strong reason to limit the vacuum advance.

That'll probably work just fine. I've found the MSD distributors usually run a vacuum can very similar to the old B30 can. That works just fine without limiting anything.


The problem these days is finding those cans. So I end up taking an adjustable can, start the limit at about 6 inches of vacuum, and then weld the shaft to limit the rod travel to about 12 degrees of advance at the crank. An engine not as sensitive to pump gas you can add another 2 or 3 degrees.

Then it works just like a B30 can.

[Formulajones]

Getting back to the cooling situation, it's starting to sound like a fan or radiator issue.

My electric fan adventures are hit and miss but most of the time.....miss. They really get dependent on how well the shrouding is made around the fan like Steve eluded to. When dad tried dual electric fans with a full shroud on his car, it just wouldn't cut the mustard. Air flow was a problem and the engine would eventually run above the turn off temps all the time, keeping the fans running non stop and the engine would just sit on 190-195 after a while, didn't matter if we were cruising or sitting still, it wouldn't budge. The fans were completely shrouded but I surmised the shrouding wasn't deep enough for one. It was only an inch off the radiator. So the areas of the radiator that the fans didn't cover were just simply blocked by the shroud, inhibiting air flow. Cutting holes and installing flaps gave mixed results, and 2 different types of fan controllers didn't help. I also think that even with dual fans, it just didn't move enough air.

Went back to the stock 69 GTO shroud and clutch fan setup and now I can't get this thing hot at all. Most of the time it runs 175 degrees on the highway in the Arizona summer heat and actually runs even cooler when putting around town at slow speeds and traffic. It will sit and idle all day and never get above that temp. Still using the same radiator as well.
On cooler days like 80 degrees outside or less, it's hilarious how cool that thing runs.