Re: Factory 289 timing vs aftermarket upgrades
That's how I give the motor the initial ignition timing it wants. At operating temperature advance the timing in 2* increments, shut down and allow to heat soak for a minute, restart. Do this until the starter drags or it spits back through the carb. Back off 2* from that point. The only time that didn't work for me is with a cam with 300* advertised duration. Be sure to adjust total advance so that it's not excessive.
70 Maverick Grabber, 5.0 (Perf. RPM heads, RPM intake, FiTech EFI, Comp XE266HR roller cam, EDIS/Megajolt ignition, long headers), T5Z w/Steeda TriAx shifter, 9" Trac Loc w/3.89:1, 31 spline axles.