I have a pontiac 400...fresh rebuild with 280 comp cam, running 850 quadrajet, points replaced with hall sensor

It wont start until initial timing is 24deg, vac adv not connected...

Checked harm balance, set to tdc manually mark falls on 0deg so that's still good-didnt slip

Question is:
do I hook up the vac adv to manifold vac port
AND retard timing a bit to compensate for vac advance being hooked up before I try to start again ?