Quote Originally Posted by pmkls1 View Post
Awesome !!! I've been wanting to see these tables for a long time now ! I'm curious about a couple values that you would have to be able to see some of the other parameters the PCM/VCM uses to calculate the "total" or "actual" timing. I would like to see what the typical timing value is at idle and what the total timing advance looks like at WOT throughout the RPM range. The way that I have the timing parameters set in my 7427 PCM is that there is no advance added while in PE. So, when looking at the open throttle timing table, the values in the 85-100kpa range reflect the total timing. Overall, the timing tables that I am using currently are surprisingly similar to these tables. Thanks for putting these up for people to see. I know that at least for me, the most difficult aspect of tuning after swapping in the vortec was the timing tables. Vortec heads are so sensitive to timing curves and are a bit different than traditional cast iron heads so they can be a challenge.
Well I'm late coming in the discussion maybe but thought I'd add.... I'm running a 350 with flat-top pistons and vortec heads here in Austin, Tex. and with compression gauge in I get exactly 10:1 when I crank her over. Cam is Comp's XE-250H, 18mm Hg vacuum, hi-Torque but dies off 4500 rpm but I don't care cuz its in a 67 K-20 with 4:55's so I'm restricted to bottom end only anyhow with the SM-420 so my focus is on torque in 1500-4500 range. My contribution is that my setup won't take more than 7 deg of initial adv. Even at 7 it has a hard time strtup cranking in the heat after I come out of a store or something when its 100 deg outside. I think its the 10:1 that prevents me from doing 10 deg. initial adv. with my cam like lots of you all write with yours. I guess I need to back initial down to 6, and put about 26 degrees into the weights in the distr. somehow so I can have about 32 deg at WOT but there's no way in heck this motor would ever take 10 deg initial adv with that cam, them pistons, and those heads