I have a 75 blazer with a healthy 454,700r4,205,44 front and a 12bolt posi rear with 4.88 richmond gears. My question is, will my rear 12 bolt hold up to the power of the big block? I have a 14bff but dont have the $$ for the gears and new 8 lug wheels. I dont do much hard wheeling but i am hard on it on the streets. If i can get away with the 12bolt i'll leave it on. What about a 14bsf? Are those any good? I'm running 37x14.5 toyos.