simple disaster

[tiglord]

I have a 1989 gmc 1/2 ton 2wd that had a 350 tbi in it,the 350 was bad and i had a 305 leftover from a monte carlo i wrecked,the 305 has 2,000 miles on it so i thought id use it instead of rebuild the 350. as the 350 came out i realized the tbi was cracked so i used the edelbrock carb and intake already on the 305. the problem is that the truck computer ran everything and now it doesnt seem to shift the transmission on time.it winds the rpms up alot b4 it shifts.i used the distributer from the original 350 so the computer could shift the tranny from the rpms of the motor. now the computer is only running the distributer and tranny and im not sure if thats enough to advance or retard my timing automaticly.im pretty lost now and i could really use some advice and/or tips for fixing this problem