ZR2 S10 8.6 rear in a g body build

[81cutlass]

Ok. You've convinced me. This is definitely going on my list of potential rear end upgrades. I'm trying to find the cheapest option I can that still gains performance. An 8.6 ring gear, posi units available, disk brakes... It sounds like a good idea.

If I could find an 8.5 out of one of the S-10's you mentioned, would your plate still fit? I can't remember but I think the housing is the same. Both are 10 bolts, right?

Yeah the plate will bolt to any 8.5/8.6 rear, just turns out the zr2 is the most common one. (zr2 is the lifted mean version like z71 to silverado). The manual 4.3 4wd 98+ unicorn rear is what you really want but i cant find one.

 

[81cutlass]

Are you using that in the 2 + 2 gp in the pic? If I'm not mistaken those have the 8.5 rears already.

Nope. Low performance 305, standard 200r4, posi 3.08 7.5. Cool car, most mundane drivetrain ever.

 

[Doober]

Cool 😀

What about gussets at the bottom and top of the uca mounts?

 

[81cutlass]

Not sure if you recall....but i believe he has an engineering degree and is working for John Deere now. Looks as if he tested the theory on software with FEA (finite element analysis) which allows one to look at weakness/strengths of stress points of given materials to ensure possible failure is absent, whew! FWIW, i once was an engineering student that thought making good $$ at 19 was better than school...my dumbass dropped out and have had regrets since!

Not run on FEA but simple enough that a bit of normal hand math is enough. Basically if the car pulls 1G of gravity it's pulling like a 1.5 60ft or something (i forget exactly.) The 1g translates to the weight of the car assuming it's all on the back axle and how everything is distributed. You could hold the plate on with 2 bolts and 1/8 plate basically. It's 1/2 plate and has 10 bolts, it's so over built its not funny haha.

Only issue I can see is the test part (this one) i used a little welder on and might have lackluster penetration on the top ears. I am going to have a buddy either tig the ears from now on or buy a bigger welder. I am going to try to rip an ear off this summer (car should run 10's) and if it doesnt (which I doubt it will) i know I welded it fine.

 

[magoo_oner]

wow nice work what's your price Hahaha I have a use for something like that

 

[81cutlass]

wow nice work what's your price Hahaha I have a use for something like that

I am going to have 3 tiers available
-Basic kit is just the rear plate, you weld and install your own upper control arm bushings. You would have to buy the kit (available on ebay or speedway motors) and cut and grind the square tubes off the UCA bushings. Estimate $150

-Medium kit is the plate and brackets. I buy the 9" bracket kit that I modify the uppers on and weld them into the plate AND weld the ears on. The bracket kit has LCA, the plate, and spring perches. That im estimating is $300.

-The "deluxe" kit $400. This kit will have everything the medium has AND a fixture that attaches the spring perches and LCA in the correct spot. Upon sucessful welding ship the fixture back to me (at your own expense) and get $75 back. So basically $325 and you no-brainer get the parts in the correct location. I welded mine up on a jig I have.

I might do these complete too for ~$700 but pickup in Iowa only basically. Not worth shipping in a crate really.

I am going to paint the axle this weekend. I also ordered $100 or so in oil, gaskets, seals, and brake parts for this. None of it I really needed (besides the oil and probably pads) but at $25 bucks a rotor it was kinda a no brainer.

 

[magoo_oner]

Ok cool can this same concept be adapted to other rearends that do not have uca ears like say a 8.8 out of a explorer or a 7.625 10 bolt from a Camaro I know a weak rearend but just curious for a mild stock build

 

[81cutlass]

The exploder rear is not very interesting to me since the pinion is offset and they need to be cut down. Not really worth it for an axle that isn't drop in ready (in my opinion). It has the wrong axle pattern also. Don't see the demand when this is the one to use.

I would have to either do it for myself or like 5-10 kits to make it worth it. I dont think I can get 5+ interested in puting a 4th gen rear in a G body and they are entirely too wide. They are 2" wider than a ZR2 and the ZR2 is as wide as you can go with easily obtainable wheels.

 

[UNGN]

Are you using that in the 2 + 2 gp in the pic? If I'm not mistaken those have the 8.5 rears already.

if only.

7.5 w/3.08's

 

[81cutlass]

Bolted on my c5 wagon wheels. Measured it up and looks like it will fit the 275's that are on them perfect. I dont have rotors on it and inside to inside on the wheels is 47.5", g body frame rails are 47.5" wide. Each rotor adds .25" so there should be .25" on the inside of each tire. 275 tire is 10.5" or so and the fenderwells are 13 wide or so.



And for drag radials I think I am going to go with this wheel. Little less BS than the vette c5 but with a 275 DR I will need the space for the sidewall. Probably have to roll the fender but I think every 275 DR on a G body needs it.
https://www.summitracing.com/parts/cll-869590675547/overview/