ok i have done about 40 tunes from 630 hp na motors to stock tunes this ones kicking my ass.i cant keep timing in any where close to where it needs to be.tryed masair ,sd tunes its a 5.3 with 5.7 heads no mill work and a cam timing pulls back to 15 degs when i have tryed hi and low octane tables set to 27 degs and a max pe retard set to 3 degs with all other modifiers i can find turned off. i just set the min timing to 24 degs and picked up 1/2second in a quarter mile.heres a tune and log any ideas would be great thanks rich