[MescaBug]

Yes. You can buy different speedo gears to accomodate a change in gear ratio or tire size.

If swapping to a 8.5" unit, you need the correct U-Joint or an adapter for the driveshaft.

[Josue]

Are the yokes different between 8.2 and 8.5?

[MescaBug]

Yes they are. I believe the 8.2 yoke has 25 splines pinion and the 8.5 is 30. The 8.2 uses straps for the u-joint, 8.5 I think uses U bolts...

I might be wrong... Its been a while since I swapped diff units!

[Josue]

I'll dive into it more. It's a good thing for these forums! Little things like this is what would have sank the project for sure. I like knowing everything I'm going to encounter before starting a project, so I can just get in there and get it done. Not have to wait a week or 2 until I get the part I need and the time to work on it again!

[MescaBug]

I always read the forum before starting a project. Better be safe than sorry!

I hate to have a car on blocks because I'm missing a crucial parts that might take weeks to find...

[Josue]

Exactly! Plus in my case, I have a 3yr old and a 10 month old, and a wife who stays home with them full time, so it's hard to balance work and them, then try to find time to work on a car for fun without making it seem like I'm ditching her with the kids more than the 40hrs a week I already do for work!

[b-man]

You will need to shorten the drive shaft by around 3/4" and change the rear U-joint (you need an adapter joint) when swapping in the 8.5 rear. The yoke on the 8.5 uses straps instead of U-bolts. Shortening the shaft is a small price to pay for the opportunity to use a far superior third member, also gives you the chance to freshen up both U-joints and have it all balanced.

Forget yoke swapping, even if they did interchange you'd be messing up the pinion bearing preload.

[Josue]

And deeper into the rabbit hole I go!!

How do you go about determining the length of driveshaft you need then? i.e.- if I follow through on the 200R4 swap, I don't recall the driveshaft requirements for that, so maybe I'd just get the trans and rear end in, then measure it out from there? Or maybe driveshaft companies would know the length I'd need for that trans/rear end setup.

[b-man]

Driveshaft companies can't tell you an exact length for any custom or swap application, but they can tell you how to properly measure to determine what length you need:http://www.dennysdriveshaft.com/how_to_measure.html

[Josue]

Seems simple enough!

[JLMounce]

Yeah it's a simple job, takes just a couple seconds once you have the vehicle in the air.

Had to do this when I installed the Moser 12 bolt. The pinion is a bit longer on the snout than the 8.2 that I took out.

In the end it was a good thing because my stock shaft was in very poor repair. The slip joint was badly pitted, the shaft showed signs of corrosion from the inside out and both u-joints were in need of replacing. I had a custom aluminum shaft built with a new slip joint, solid 1350 series u-joints etc.

[Josue]

That's a good way of putting it too, because like I said, this car is just about 95% original mechanically, so having to replace all this stuff would be a good idea anyway!

Who did you get your driveshaft setup from?

[Doug Hopkins]

Originally Posted by Josue

That's a good way of putting it too, because like I said, this car is just about 95% original mechanically, so having to replace all this stuff would be a good idea anyway!

Who did you get your driveshaft setup from?

I had mine built at Columbus Joint & Clutch. (Ohio)

[Doug Hopkins]

Originally Posted by Josue

Are the yokes different between 8.2 and 8.5?

You might consider using the stronger 1350 yoke that Moser and Jeg's offer for the 8.5, and having the matching joints installed in your driveshaft build.

[JLMounce]

Originally Posted by Josue

That's a good way of putting it too, because like I said, this car is just about 95% original mechanically, so having to replace all this stuff would be a good idea anyway!

Who did you get your driveshaft setup from?

I had mine done locally. Northern Colorado Driveline. They have a reputation for quality work and the price was much better than some of the widely used online shops. It cost me $340 in total for a complete driveshaft, slip joint and solid 1350 series u-joints.

[Josue]

Nice. I'll have to look into locally sourced shops then, like you guys did.

Doug - Did they build you a whole new driveshaft? Or you had your stock one modified/repaired?

[Doug Hopkins]

I took them my busted shaft They used the front yoke (TH400). They then built a shaft that would handle 550 HP with tires . New shaft and joints with a 1350 joint at the rear and balanced. It was $275 out the door. The guy that runs Columbus Joint & Clutch is a racer, so he knows what it takes for a driveshaft to live. The shaft itself was larger than the stock shaft. You give him the distance from the rear trans seal to the rear u-joint center of the yoke with the rear under load, and he will build it in a day.

[Josue]

Damn, not bad at all! Thanks for the tip!

[Josue]

Checked with the neighbor tonight, I was wrong, it's only a 8.2 10 bolt. I guess I could still go with it if I wanted to save a good bit of money for now, and I wouldn't even have to do the driveshaft or anything yet.

It all depends on what I'll do with my budget...if I want to drop most of it on a 400 build, then I'd get a better axle from Jim. If I end up just keeping the 350 in there for now, spending money on brakes, suspension, OD trans, and wheels, then the 8.2 with 3.08 posi will be just fine I'm sure.

[b-man]

Grab the neighbor's 3.08 geared 8.2, even without a posi it's worth more than $100.

It will give you a nice boost in street performance and still be decent on the highway.