i have a 1973 307 sbc, 2 barell carb, hei ignition,bone stock only mod. is long tube headers this is in a 1979 k5 ,my question is what degree is base timing set at ? and should my vacuum advance be hooked to direct manifold vacuum or not and the same with my egr valve what type of vacuum should it be ran to ? please help

 

The EGR valve should be connected to the EGR solenoid and then to the intake manifold.

I always prefer to have my distributor vacuum advance plumbed to a direct manifold vacuum source.

Base timing... I would adjust base timing for the maximum engine vacuum at hot idle in gear. Do this with the vacuum advance disconnected. It should be somewhere around 8-10 degrees advanced.