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

The harmonic balancer may be "spun", causing the timing marks to be WAY off. You could also have retarded valve timing.

I've had this same problem before - what I found is that I hadn't put the distributor in correctly: Although the crank and cam marks lined up ok, the rotor in the distributor wasn't pointing where the #1 spark plug position was supposed to be.

They'll still run, if you jack enough other stuff out of shape. Moving ignition wires one 'clock' position, twisting the distributor around, etc.

Been there, done all that. And still get this one wrong, after having done several engines. :banghead:

So, I'd put the #1 cyl. at TDC while making sure that the intake valve has just closed, and see where the distributor rotor points. Adjust the thing as necessary, until it comes out looking like the manual says it should.

Once you get the timing issues sorted out, I'd be willing to bet that your vaccum readings will come up.

Good luck!