Fine Tuning GMPP Motor...........Please offer up some advice

[79cutlass]

Ok first of all here's the combo: GMPP 350H.O. 330hp out of the box.. mods include Comp Cams XE274 (230/236* at 0.050, and 0.487/0.490-inch lift, 110-degree lobe separation), Vortec heads milled down about .025 + thin fel-pro head gaskets(compression is close to 10:1), studs and corresponding Comp springs installed, stock HEI distributor/MSD High-Voltage Module with built in rev limiter set at 6000rpm, has 1-5/8" Long tubes into x-pipe and 2.5" dynomax bullet duals. '97 T56 6 speed and 4.10s. Currently has a 1405 600cfm Edelbrock but I have a 1407 750cfm Edelbrock waiting to go on. I am trying to get it dialed in and I have a few questions...

1.) What should I set the timing at? It's only adjusted by sound right now..It's pretty close but I am going to put a light on it to get it perfect.

2.) I have a distributor advance curve kit with three different sets of springs. Which set should I run?

3.) The 750 carb came with an assortment of primary jets, secondary jets, metering rods, and step-up springs. A performance tune for a 750cfm out-of-the-box is as follows Primary Jets - .113, Secondary Jets - .107, Meterings Rods - .071x.047, with an Orange step-up spring. Should I set it up like that to start off or change something?

4.) Any other suggestions are greatly appreciated! I am shooting for high 12s with slicks when I go to LaRue on May 30th. Thank You