20 years ago, i bought a strange 12 bolt with posi for my lt1 car for I think about 1900/group buy, yes i know prices go up. Over the years I've seen it rise up to about 3k and that seemed ok.

I just looked and priced out a hawks 8.8 with a posi and wow, 5400!!!! wow. I'm curious what is still reasonably to buy anymore for a street car that is not a 10 bolt.

EDIT 93-02 rear ends.

 

Which 10 bolt? a 8.5" built correctly can handle a lot of power and not have the 12 bolt tax.

the 7.5? errrm....

 

A fully optioned midwest chassis fab 9 is cheaper than that hawks 8.8 and is a way better option

 

Still over 5k with a posi and that's not picking all options either.

 

i'm talking fbody fitment.

 

8.5" did come in F-bodies, just not a 4th gen. 2nd gen would have been the last factory fitment. I think I remember someone custom fitting one into a 4th gen at some point, it was cost prohibitive at that time but that was when direct fitment stuff was cheaper than today. Still though, it's not like 8.5s grow on trees these days; common in the '70s, but after that it was only used in a handful of G-bodies and I think some version of it continued to be used in certain trucks for quite some time? I'm not well versed on the truck rear ends though.

He's right about the 8.5 being a great rear though. There is almost no compromise in strength compared to a 12-bolt; they can be setup to handle a lot of power. I have one in my '71 and it's extremely beefy compared to a 7.5".

 

https://www.strangeengineering.net/p...osi-unit.html/

 

A 7.5 can hold a decent amount of power if you run a lower (numerically) gear ratio. It's more efficient too and lighter. If you have enough power (turbo car) and can get away with 2.73's (yikes) or 3.08's or 3.23's then It can live easier than 3.73's or 4.10's. Why? Well imagine using a taller tire, what does it do? It puts more contact on the ground from the larger diameter. Well a 2.73 has a very large pinion and therefore more teeth are engaged in the ring gear at any given time compared to a 3.73 and up gears. Imagine only having 1 tooth contacting at any given time vs 2 teeth or more. Most people do not consider WHY the 7.5 is weak. When you go up to a 8.5, everything grows in diameter, including the pinion, so you automatically have more teeth engagement because of this.

 

yup aware of that fitment, i meant specifically for 93-02 fbody options. should have been more clear.

 

I think the Dana S60 (but maybe I'm biased) is best in terms of strength and factory fit. it drops right in and the only thing is you need a couple bolts/nuts to hold your sway bar on. Totally perfect on the street.

The only downsides are weight and 3.54s being the numerically smallest gears you can run.

Of course you'll be looking at close to 4k all said and done, but that will include a driveshaft too.

 

gear ratios is where these get tough as well.....can be tough depending on what trans you are running especially auto to fit the goals of the car.

i had the s60. only regrets was not getting it powder coated and abs issues like most other rears

 

Or you can run an aluminum driveshaft and hope it breaks before the 7.5 inch rear.

 

@Kfxguy @wannafbody totally makes sense and get this use case. my point is aftermarket options...after the stock rear end...the next only option to run a posi that is not a 7.5 rear will cost 4-6k. that's my WOW reaction. there is nothing in-between.

 

https://shop.brutespeed.com/moser-9b...g-axle-package
https://shop.brutespeed.com/moser-3m...n-third-member
https://shop.brutespeed.com/pst-dra3...yoke-pst-dra35

$3823.00 shipped if you don't want 3 or 4 channel. Bob

 

A third option is if you have the skillset and equipment you can modify a boneyard 8.5", 8.8" etc. housing to fit your F body.

 

I know my Moser has gone up a good bit since I got it back in '21. I look every so often just to see. Would definitely be a bit more painful now!

 

1900 was a good price back then.

I want to say my Moser 12 bolt with a couple options (eaton posi, 33 spline axles, 4 channel) was around 2300 before shipping, bought in spring of '04. The Strange was usually a couple hundred more.

 

You can get a used 12 bolt out of a salvage yard @ a reasonable price.

 

My S60 was a smidge over $4k last summer. A similarly equipped MWC 9" would have run $5k-ish. Still have to tidy up some things on the S60 like brake line routing. Looking back I could have just sold off my UMI torque arm and went MWC for possible true dual action.