64 394 4bbl ignition timing??

[Jakespeed63]

Recently rebuilt the engine in my '64 starfire. Retrofitted Pertronix ignition in place of the points and condensor. My '63 factory service manual lists the setting at 5 dgrees BTDC.
My question is: The factory 4bbl seems to use a manifold vacuum port for the distributor. So, this increases timing to over 20 degrees with vacuum line plugged in. Enigine was bored .030 over and valve seats are hardened. I always run at least 93 octane fuel. Kinda concerned about doing some damage to this new engine. What is everyone else running for timing and what is total advance at say, 4,000 rpm?
If anyone has ever set timing with a vacuum gauge, then with maximum vacuum acieved at an idle, base timing is about 15 degrees, 35 deg. w/ vac. Camshaft has been reground to a very mild "RV grind" by Egge machine. Seems to idle very smooth and have decent power but....???
Thanks, JT