Low vacuum

Recently rebuilt a 351W and installed SEFI. When I initially started the engine, I had to rotate plug wires around the cap one spot in order to get the engine to fire. When I attempted to time the engine, I noticed the timing marks were off significantly - about 30 degrees AFTER TDC - not BTDC. Engine ran fine though. Next, I noticed I was only pulling 8" of vacuum. Before buttoning up the engine, I did ensure cam and crank marks lined up on TDC. Any advice on where to start fixing this problem cause I assume they are both related to one another. Thanks for the help

what do you have for a cam?

did your timing jump?? did you install a new timing chain when you did the motor

Found out the HB is mismarked for my application. The engine is an 84 and the HB from NAPA is for an 85 on up. Didn't think it made that big of a difference, but when I took it off and lined the new HB up with the old worn one according to the key position, there was a 20 degree difference between them. I remarked the new HB and now have 18" of vacuum