383 back fire !
also, if you did a cranking compres. test, that would answer that for you. atleast, let you know to look closer there or not. if you have less then 150 cranking press, with the sp plugs out, full battery, and the throttle held open. should be in the upper 100's. like 175. seen lots higher then that, but a typical 10.5 compresion sbc will be in that area. sorry for not goin back to remember what your particular eng. setup is. could even be in the really low 200's if you had a high compression motor.



