vacuum gauge to solve idle issue

Ok, I missed that; 3 wasn't 3. I'm glad I didn't say the gauge was lie-ing!

And so;
>if you were getting 5 or 3 at the spark-port then the primary throttles seem to be waaay too far open. The spark-port should be dead,zero vacuum at idle.
>But now, 14" at 775 is a good number; too good for that cam. It seems to indicate that the timing is too far advanced.
> These two are contrary, in that, they normally do not go together. So then the first thing I would do is set the Transfer port synchronization. This will get the low-speed circuit back in operation and kill the sparkport. Your Idle-Timing will likely end up around 12 to 18. But there is no telling what the idle rpm will end up at. Once the T-port is synced up, you cannot adjust the idle speed (much) with the curb-idle screw. Idle rpm will have to be set with timing and idle-air bypass.But; the valve lash will have to be known to be correct first.
>I'm struggling to figure out why your engine is not pinging with so much initial advance.(Unless the rate of advance is really slow,super-slow, or the secondaries are not opening.).
Once the T-port sync is set, the idle-timing will come out in the wash. Then you will have to engineer the power-timing and rate of advance.
And then, finally, the VA can be experimented with.

As a point of reference, the engine usually will accept 30 to 40* or perhaps a little more,of timing, at 1800 to 2500 during part throttle operation; so 25 to 30 is not a big deal with a stick-car or an auto with a loose TC. But generally, with increasing load, this has to be pulled back,to 25/30. Usually the power timing will come in at 25/28 @2500 to 3000 and could be as much as 35* by 3000 to 3600. Generally, 36* is the max for SBMs. And the less it wants, generally indicates an efficient chamber, while the more it wants, generally, indicates one less so. Notice the generous use of the word generally. Every engine/combo has it's own personality, and it's needs can change with it's environment, and it's tune.