Torque Arm Rear FS

[NixVegaGT]

Hey team. I figured I'd post this to the list before my local craigslist. As some of you already know I moved to plan B on my project and that included fabricating an adapted Miata/Rx7 IRS. SO I'm not going to be using the setup for plan A, a 7.5" torque arm rear. Here's the specs:

7.625" WS6 torsen unit with 3.42" gears. The pinion is adapted using the bearing change vs. cutting down the pinion shaft OD. It uses 28-spline axles and I've also installed an adjustable rear cover gusset. The panhard bar and torque arm go with it. I've modified the dust plates with mounts for disc brakes if that's something that is interesting to you as well. I've got the calipers and discs I used for that setup. It's ready to bolt in as is. I had it all mocked up before I changed my mind and went with plan B.

I'm in Minneapolis for anybody local. I'd prefer not to ship this so anybody interested in the next couple weeks just let me know. I'd also rather just move the whole setup along vs. taking it apart and I've decided to eat it on price a bit that way.

$300

Let me know. Thanks!

MonzaRear1.jpg

MonzaRear2.jpg

[olds70supreme]

I'm really intrigued and live about 1.5 hours from you, but am in the middle of a shutdown for work and don't have time to figure out if this will work for me. I'm guessing that the 7.5 isn't the end all-be all of rear ends, but it must be better than the stock 6.5, right? Any other benefits?

[Monza Harry]

.... I'm guessing that the 7.5 isn't the end all-be all of rear ends, but it must be better than the stock 6.5, right? Any other benefits?

Yes It is stronger than a 6.5, and there are lots of parts available now that weren't around for these rears 20/25 yrs. ago, and it is considerably lighter than an 8.5" or 12 bolt for starters, and smaller which will leave more room for exhaust as well! I was originally considered the 8.5" 10 bolt but for the sake of actually finishing the project, and some of these reasons, I have decided on the 7.5" Monza rear (or alternately the 7.625" Camaro/Firebird for off the shelf gear selection) with a pile of upgrades, same ones I was going to make to the bigger one anyway, and these parts are marginally cheaper as well! Also a plus for the 7.5", is it is available in torque arm, 4 link and leaf spring varieties off the shelf (4 link will need to be narrowed from a "G" body Monte/National, etc.) S10 (leaf) and Monza (torque) are the right width already, Camaro rear is also a torque arm, some with the 7.625" and some of those hard to find ones will come with goodies already in them but will need to be narrowed Harry

[NixVegaGT]

Thanks for picking that up for me, Harry.

Here's some info as it compares to your (olds70supreme) 6.5":

The 7.5" and this one in particular is quite a bit tougher than the 6.5" for a few reasons:
• Late S10 28-spline 5-bolt axles (Much larger diameter and stronger) vs. stock 6.5" 26-spline 4-bolt axles. I didn't realize how major the difference was for this until I got the axles. WAY fatter.
• Uses later 7.625" pinion/ring gear (3.42) and I added a WS6 Torsen Posi (The torsen is a really great progressive posi for track racing)
• Double welded axle tubes to the center section (I jigged the rear and welded up the axle tubes. This helps add a bit of strength)
• Aluminum cover gusset (This includes adjustable buttons to support the bearing caps through the housing)

There's some experience with drag racing with the 7.5" rear. Most of the numbers I've seen say 300 rwhp as a limit. I spent a couple days dialing in the gears. (OMG! I will NEVER do that job again! LOL). For your car it's a significant bolt in upgrade. I probably spent around $600 building this. Now that I've changed my formula to the IRS it's pretty much just in the way on the floor of my shop. It'd be great to know it was getting used.

I just finished my rear mounted alternator mod on the RX7 differential. Here's a couple pix:

RearAlt1.jpg

RearAlt2.jpg

FUN!

[Monza Harry]

No Problem Nick just glad to see you back and working on your car! I was just sharing some of my latest thoughts on this subject. I have been looking at my brothers 8.5" and helped him move it when I decided a re-think might be in order, I have a pretty low expected curb weight goal for my car and everything I want is taking this the wrong way, so a new plan of attack was needed to reach my latest original goal, I am sticking to the spirit of this plan, just a little undecided on the best route to get there. Harry