What I do with ALL new engines is I screw a mechanical oil pressure gauge into the sender fitting right there on the filter housing. Then when I prime it with a priming tool I can see what is going on. Also when I start it I can see the oil pressure at all times. I begin with disconnecting the rubber fuel line at the pump so no surprises. To set the timing I first get the rotor pointing to #1 at TDC making sure it was a compression stroke. I position the advance can where I have the most swing for adjustment. On a Buick 350 this usually means right between the alternator and distributor. Then I remove all the spark plugs, pop them back in the plug wires, ground them against the intake manifold, hook up a timing light to #1, and set the timing while someone else is cranking the engine. While the plugs are out it will spin nicely without any advance spoiling the timing. Put the plugs and wires back on. Connect fuel line. Now your timing is rock solid and you can start the engine and set the RPM's to whatever the cam manufacturer wants you to for a break-in period. Watch the oil pressure the entire time as well as listening for expensive noises.