6literc10

have a lt1 in a 56 chevy that is having starting issues. by the symtoms it seems to be flooding. it currently has 36lb injectors compared to the stock 24lb ones. i changed the calibration to 36lb and alot of other areas (32lb, 38lb, etc) to check but it doesnt start. after we crank and let off the key it seems to fire backwards a couple of random times. we check for correct power during crank and key on and its all correct. we swapped plugs and tried another maf to make sure and it doesnt seem to help. weve successfully got it started quite a few times from extensive cranking and even having to warranty the starter. once its warmed up it seems to start alittle better but if you start it the wrong way (let off crank when you think itll start but doesnt) it will do it again. not sure what to do any help would be appreciated.