Wagon 8.5 swap

[blackbuck350]

Ok guys needing driveshaft length help, tonight I finally got my 8.5 from a 87 Buick GN, mounted in my 81 wagon, has anyone made this swap? if so what was the length of the shaft? My shaft measures 54” from tube to tube, it seams to be about 2” too long

 

[Ribbedroof]

What trans is in the wagon?

The 8.5 requires a shorter shaft than the 7.5, if nothing else is changed. You will need a shaft from a coupe, sedan, or wagon that had an 8.5 installed with the same trans you are running. 8.5s were only production-installed in Olds and Buick coupes (442, Hurst Olds, and Turbo Regals) from '84 onward. No other G body had a factory-installed 8.5 rear, including diesels and wagons.

Thre are instructions on h how to measure for driveshaft length in several places on the web.

 

[blackbuck350]

What trans is in the wagon?

The 8.5 requires a shorter shaft than the 7.5, if nothing else is changed. You will need a shaft from a coupe, sedan, or wagon that had an 8.5 installed with the same trans you are running. 8.5s were only production-installed in Olds and Buick coupes (442, Hurst Olds, and Turbo Regals) from '84 onward. No other G body had a factory-installed 8.5 rear, including diesels and wagons.

Thre are instructions on h how to measure for driveshaft length in several places on the web.

oh forgot I’m running a turbo 350 with a LS 1

 

[blackbuck350]

What trans is in the wagon?

The 8.5 requires a shorter shaft than the 7.5, if nothing else is changed. You will need a shaft from a coupe, sedan, or wagon that had an 8.5 installed with the same trans you are running. 8.5s were only production-installed in Olds and Buick coupes (442, Hurst Olds, and Turbo Regals) from '84 onward. No other G body had a factory-installed 8.5 rear, including diesels and wagons.

Thre are instructions on h how to measure for driveshaft length in several places on the web.

Also ribbedroof do you know if the u joint from the 7.5 fits the 8.5 or do I need to get a u joint for a turbo regal 84 on?

 

[gnvair]

On factory G body 8.5 applications there is a 1" shorter drive shaft that is used with them. The only way it would be different is if your engine and transmission are no longer in the factory location. Also, all 78-88 A/G bodies have the same wheel base length. Only the El Caminos are different with them having a longer wheel base.
The G body 8.5 uses the same 44R series u joints as the 7.5.

 

[oldsmobile joe]

Factory installed turbo 350 and 200-4r is is the same length.
The bigger question is did the transmission move forward or rearward with the ls engjne install.
I would start measuring.

 

[blackbuck350]

On factory G body 8.5 applications there is a 1" shorter drive shaft that is used with them. The only way it would be different is if your engine and transmission are no longer in the factory location. Also, all 78-88 A/G bodies have the same wheel base length. Only the El Caminos are different with them having a longer wheel base.
The G body 8.5 uses the same 44R series u joints as the 7.5.

I tried using the driveshaft from my wagon, which I was told should fit fine, but it’s about 1 3/4” too long

 

[blackbuck350]

Factory installed turbo 350 and 200-4r is is the same length.
The bigger question is did the transmission move forward or rearward with the ls engjne install.
I would start measuring.

And no everything is in the factory spot

 

[gnvair]

I tried using the driveshaft from my wagon, which I was told should fit fine, but it’s about 1 3/4” too long

Well, whatever swap mounts you used put the engine end transmission into the wrong spot.
I will tell you straight up that GM only had one drive shaft for the G bodies that used the 8.5. It was 1" shorter.
If that shaft doesn't fit then something is off where your engine and transmission are located.

 

[fleming442]

Fleet Pride will build you one for about $200