Setting vacuum advance
I hooked up the vacuum can on the dist and it gets too much advance - we're talking high 50's.
How do you know that's too much?
If your D is locked at 35,
and your total from all sources is 50,
then your V-can is only bringing in 50 less 35=15.
If the V-can is plumbed to manifold vacuum,and
if your stall is 2000, then 50* at 2000 under load, YES, that will be too much, and pinging is the evidence.
But if your stall is 3500, then, then the vacuum will rapidly drop as the engine goes towards WOT, and will soon drop too low to activate the V-can; so yur good to go.
In between, will get you varying results.
The goal of all timing mechanisms is to START the burning process at the right time for the engine to achieve maximum cylinder pressure at a specific crank position, to impart to the crank, the maximum amount of push. This position is about 25 to 28 degrees after TDC. The amount of ignition advance required to achieve this, from idle to about 3500rpm, varies with rpm and load. After 3500 or so, at WOT, the advance requirement usually varies very little.
The biggest cam I have tuned is the 292/292/108, and I only tune SBMs; and only for street. I can tell you that for best results, that tune required a "normally working" distributor. That is to say; Not locked, and ported vacuum advance.
And at a cruise rpm of 2600, it liked over 50 degrees.
With a 4-speed, a car will hit 2600 FOUR times at Part Throttle, before hitting hi-way speed.
You can easily figure out what no-load timing your engine wants at any rpm, just by bringing the rpm to that specific point and attempting to keep it there, while advancing the timing. When the rpm no longer picks up, you have found the maximum no-load timing. You can build a map by doing this every say 400 rpm, from stall rpm to cruise rpm, or a little higher. Then smooth it, and I subtract 3 degrees for cruise-load.
If your engine is too loud to hear detonation, I want to say bad things to you and about you, but in your case, I understand that the car is Not a streeter, so then, you will probably want to invest in a stand-alone knock-sensor. Then you can build a street power-curve.
