thunder bolt IV timing questions
 

ok trying to get my timing set, ive got an sbc w/vortec heads and thunder bolt IV ignition. its v8-24 module. with timing set at 8*btdc i can only get around 25* total advance at 3700 rpm. according to all the charts ive seen it should be all in by 3700 rpm. is there a chance that the module is screwed up or is it more likely im looking at the wrong chart someway and somehow and i need 4500 rpm to get timing all in

If you are idling at 750 rpm, you already have 6 degrees advance added in by the module.
Seems to me at idle you are mechanically set at 2 degrees, and the module is adding in another 6.
Run it to 2000, set your final timing where you want it, (I'm guessing you are looking for 32 degrees?), bring it back to idle, and you'll show, depending in idle, somewhere around 8 from distributor orientation + 6 from advance at 750 = 14 degrees at idle.

Here's the advance curve. (I'd post a pic of it, but I can't right now). The curve shows an error of +/- 1.5 degrees.

Add these to initial at the below RPMs to get what the 24 does

Straight line slope
500 rpm - zero advance
750 rpm - 6 degrees
1000 rpm - 12.5 degrees
at about 1200 rpm = 16 degrees

At the above point, then the curve flattens a bit
1500 rpm = almost 20 degrees
at about 1900 rpm, it's all in at 24.