Change Sb Towers To Bb Towers Problem

[ira ashley]

I CHANGED SB TOWER FOR BB TOWERS; EVERYTHING BOLTED WITH NO PROBLEM. MY PROBLEM IS I CAN NOT GET THE 402 MOTOR WITH MOTOR MOUNT BRACKETS TO FIT ON TO THE MOTOR MOUNT WHICH ARE BOLTED TO THE TOWERS. THE MOTOR LIKES ABOUT 1/2" GOING IN ON BOTH SIDES (THE TRANNY IS A 400TH & IS BOLTED IN PLACE).....WHAT I'M I DOING WRONG?????
THE 402 WITH ALL THE BRACKETS DONOR TRUCK WAS A 72 C30, THE TRUCK I'M PUT THE 402 IN IS A 71 C10........MAYBE I HAVE THE TOWER ON WRONG? NEED HELP!
THANKS IRA