I decided to check my base timing for the hell of it tonight. When I checked it, I checked it about 1200 rpm, I could get a better look at the balancer at that speed. It looked like the timing was set about 9 degrees. I know that typically these 502's are set at 8 degrees, but how much does it really matter if it's 8-10 degrees. I know my timing was at 13 degrees once upon a time, and the idle wouldn't come down. I set the timing between 8 and 9 degrees. The only real difference I could tell, was 8 degrees had a little bit lopier idle than 9. If the timing is set to 9 or 10 degrees, doesn't the ignition control take over and change the timing on it's own above 3000 anyways. Is total advance going to be different if the base timing is set to 9 vs 8? Thanks.

set at 10 good clean idle then check total timing at 3k. If it is carbed do total timing with the proper light at 3000 depending on your fuel grade between 32 to 35. This is the most important thing to watch and set it then. The ramp up to that will depend on your springs. Of course this depends a lot on your ingnition.

I have a Gen 5 MPI

so computer controlled. Set Base at 10 computer takes control from there. You can check again at 3000. to make sure you are at I think it should be 32 or 34.

If you set the timing at 9*, then the engine will have 1 more deg. everywhere. If you set it at 12*, then it will have 4* more everwhere. And so on. The timing is programmed into the ecm. The 8* setting is a starting point for the ecm. The ecm doesn't know what the actual timing is. It only knows what it is programmed to do.
Eddie

You can not check total timing on that engine. The timing is constantly moving if you rev the engine up. That is why you have to put it in base timing mode to set the timing. If not, it will bounce all over the place.
Eddie

That is all true I havent messed with one in awhile you usually dont have to do anything to them(: Oil gas and go
What should base timing be at? Is ten to high

I've got mine set best I could tell betweet 8 and 9 degrees. Put it in timing mode by shorting A and B on the diagnostic port. As far as I know, once you set the base by doing that, isn't anything else to do. Computer takes over from there.