[fireforsin]

Can soemone assist me on changing out the springs and weight in a GM HEI? Just curious whihc weights and springs will do what. I just put 2 "heavy" springs in and i don't know what it did. I also put in an adjustable vaccum advance canister. My engine is a 350 stroker "383" with com cams 207H and domed hyperutenic(?) pistons. MY heads are 74cc world products s/r i believe. So maybe someone can give me some advice on what type of springs and weights I should use.
Thanks,
Mike

[DoubleVision]

I would use the lightest springs, most high performance small chevy`s like 12 degree`s before top dead center, and 38 degree`s total all in by 3000 RPM, set it like this with the vacuum advance disconnected, also make sure your vacuum advance is connected to a ported source, or one that pulls vacuum off idle and not at idle. if detonation or spark knock is detected, back off the timing 2 degree`s at the time until it stops, then the timing is set.

[fireforsin]

well thanks for the info. i first tried one heavy sring and one medium but when i started it up i heard LOUD! backfire type sounds, i heard two and then i shut the car. but it is possible that i might have mixed around one of the spark plug wires, would this cause the backfiring sounds?