just bought a 78 malibu it has a 8.5 BOP rearend i think? from what i could find on the gear set part number comes back as 8.5 4.10 i dont think it has c-clips. it has a long tail 350 tran and a 50in driveshaft center to center. my guess is i need a 53in shaft for a short tail tran. but that doesnt match up with what ive read here and other places. i thought i would need a 51.5 inch driveshaft any thoughts. thanks