My point was that the car was faster, more mph with more total timing when the dyno said it was making more power with less timing. The only thing I could come up with was the car was getting more air at speed because it didn’t like how it was jetted for the track either.
Another factor is how fast the rpm changes. A slow full throttle acceleration in high gear, or even worse a constant rpm (such as maintained top speed or running in a steady state dyno) can keep the engine in the zone where it is most sensitive a long time, let heat build, and detonate and/or lose power, while a fast sweep through the rpm range goes past that rpm quickly and may be able to handle more ignition advance and/or leaner jetting to produce more power. The result can be that an engine that is perfectly tuned for peak power in an acceleration dyno that runs the engine through the rpm range quickly may go into meltdown ten minutes later when held wide open on the highway at top speed for longer time. Dynos are great tools, but just like all other tools they have quirks that you need to know about to get the best results.
I agree with you but the fact that the carb was too fat for the dyno and the timing didn’t make power like it did at the track let me to think about clean air.
What distributor do you have? MSD SBC distributors max out mechanical advance WAY high, the springs (they come with) are the stiffest. Confirm your TDC, set initial at 12-14, wind it up and see where you max out on mechanical advance. Then try some lighter distributor springs. a distributor machine only becomes relevant when you get to the nitty gritty of changing the bushings, etc.. With my 327 Chev, I ended up at 14 initial and the middle of the road springs to get it happy - would never have imagined that I'd be there without pinging like hell. Make sure you journal what you do along the way, so you can look back and study your results.
I have an old Allen machine that's been made to run points and HEI. It will run up to 6200 rpm. I am now working on a '67 GTO points unit. Going off the factory shop manual, Pontiac calls for 0-2 degrees @ 500, 10.5 - 12.5 degrees @ 1000 rpm, and 13-15 degrees @ 2200 rpm. ( Distributor degrees ) Timing was set at 6 btdc, the advance was already moving at idle ( 600 rpm ).
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