Was thinking of adding a vacuum advance canister

BIG cam, big duration, 35* overlap.
I read somewhere that big cams don't play well with vacuum advance.

 

5 psi should be enough to make the vacuum advance open, try before you buy though to confirm.

I can brig a dis over with vacuum advance on it you can hook up to your engine to see if it works when it goes back together and in your car.

 

Thanks Larry, wasn't sure where the stock V/A came in at.

Well Mart is gonna have another 13 cid to tame that HUGE cam he has, so maybe he'll have an extra 1'' or 2" of vacuum from the extra draw?

 

That's the concern I have about vacuum advance, it "might" help.
I don't have any pinging now with 11 to 1 and iron heads, and my roller is smaller.
Im concerned if I were to add vacuum advance (however it would be added) that I'd open a can of worms, and I'd just end up removing it. We'll see once the weather gets warmer as far as pinging

 

Your not even going to need it, as soon as you hit the gas you are at 2 grand 500 more and you are up on the mech advance all in @ 2500 right. The only place that vac advance is going to work is from idle to 2 grand. You have a what 2500-3grand stall and if that is so the vac advance I think is useless.

The only place it might be a benefit is if you are in 4th gear with the convertor locked up and you are moving at 1500 rpm and just want to cruise up the hill. I am at 2200 at 65 mph If I go slower I drop to 3rd and just lock up the convertor again or unlock it, stay in 4th and let the convertor rev up it adds about 200 rpm unlocked.

I have never had a problem with off idle now if I had a 308 gear and a 1500 stall that would be a different story All 3 of us are up on the rpm the moment we hit the gas. Ok you might get 1 more mpg big deal.

I gave it more thought and it might work at 15-2 grand cruising down the road since you will be at about 15-20 on the vac gauge at that rpm and that slight touch of gas is where the advance might work but I think you would have to have an adjustable advance system to take full advantage of the advance canister.

 

Yep Im just leaving it as is, you bring up some good points, my total timing is all in at 24/2500 rpm, my typical highway cruise rpm is 3000 to 3200 rpm. Around town who cares, idle to 2500 rpm, then a red light, idle to 2500 rpm, then another red light, repeat again. The majority of my driving is 2500 rpm and up, mostly highway.

 

Darnit Larry, now Im thinking again

 

Mark, with all due respect (Ricky Bobby reference) you don't drive the car enough to be concerned about gas mileage. It's also modified enough for performance that you are not going to get good mileage anyway. I don't run vacuum advance on any of my modified engines. My blue car still gets over 20 mpg without it. They really only come into play at steady cruise speed (no load) or coasting. Either way the throttle is not open very much. Don't loose any sleep over it.
Then again, we learn by doing. And testing. Maybe it would be a good excuse to work on the car.

 

Your right Steve