Since I don't have any knowledge about weights and springs, could some clue me in on what would happen if tighter springs were installed replacing the old tired stock springs? Does this effect gas mileage and performance? thanks.

Yes tighter springs alter the advance rate thight springe slower advance lighter springs faster advance rate.What i did was one light one heavey that is the advice i got from our tc buds it has work for me.Hop this helps.

Snake, At what starting point do you have to re-time the crate 350 stock engine 245 hp? Do I just pick a number like 8 BTDC and work from there to experiment with?