ok so i'm trying to get the timing right for my engine. i set it at TDC at 0 and put the rotor touching the 1 on the cap. didn't work and it would backfire out of the carb. set the timing back a little bit by putting the dizzy off a tooth and it starts up but will not idle above 500. i have no timing light so i'm just trying to get the truck to a point where i can get it to idle decently untill i can set it up perfect. help?