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Old 05-13-2008, 04:21 AM
79cutlass 79cutlass is offline
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Default Fine Tuning GMPP Motor...........Please offer up some advice

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
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Old 05-24-2008, 09:26 AM
Shaker455 Shaker455 is offline
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Default Tuning

79,
Start by setting the curve on your HEI....is that the one that came with the engine?

If so that has MSD's advance set up in it so that's a good thing!

Start by installing the black 18 degree bushing with the 2 light blue springs and getting initial about 16 to 18 degrees to start.

I'm not afan of the E-carbs but start with the 750 out of the box and hook a vacuum gage to a small full source and tune both screws to get the highest vacuum reading.
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