What is the correct length for a driveshaft for a 70 GS455 with a TH400 and 12 bolt Chevy rear end? And what is the correct length for the factory driveshaft? Previous owner put a 12 bolt Chevelle rear in and I’m trying to figure out if he kept the original Buick driveshaft or modified it or installed a different one. Thanks!
I don't think the GS ever came with a 12 bolt rear from the factory. I know some Canadian built Skylarks got the Chevy 12 bolt with 2.56 gears. The GS cars got the 8.2 and 8.5 10 bolt rears. For those rears, 1970 455/400 with 8.2" rear end, shaft should be 55.10". Brown/blue tape. 1971 455/400 with 8.5" rear end, shaft should be 54.241".Yellow/green tape In any case, if I was you, I'd have a new driveshaft made. I'd ask the drive shaft shop how they want you to measure. https://www.dennysdriveshaft.com/how_to_measure.html
The previous owner blew out the rear end before he sold it back in 2001. I bought it as is with the 12 bolt 70 Chevelle rear end and TH400 transmission from a 73 Pontiac. As I’ve been doing a frame off restoration, I’ve learned what a hodgepodge drivetrain I have. I just wanted to make sure what it should measure. It currently measures just over 53.5” I didn’t know if anyone did a 12 bolt conversion and knew the length of their driveshaft. I’ll check the site you mentioned. Thanks.
