bunkerbuster

I am looking for suggestions on what Rear End to put in my 99 WS6 Trans Am. Given the following variables, it may not be as simple as saying "Ford 9 all day". *ONE Thing to keep in mind: I need a solution that will bolt right in. Welding or any clearance-ing is out of the question.*

Here is what I am working with:
-500RWHP
-Naturally Aspirated
-built 4L60e /w about 2500 stall TQ Converter
-UMI Rear Coil Over Kit (Part #: 2046-125)
-UMI Rear Suspension (Part #: 203538)

Here are my expectations:
-Mostly for the Street, but could drive it to the track then back home
-Looking for best bang for buck, but not at the cost of reliability
-Currently, the old setup has 1.2" drop eibach springs. I like the way it sits. So, I will adjust the coil overs to roughly match that height. (I have heard people with the Ford 9 have problems with it scraping the ground?) This would be no bueno.
-I am open to any platform or any vendor.

Currently what catches my eye:
Hawks Performance 8.8

dannyz

You don't need an upgrade.
The stock rear behind an auto is more then enough for what your going to throw at it.
Save your $.

bunkerbuster

I do however need a new rear end or a rebuilt one. Mine is not yet bad, but I suspect it is on its way out. I was just looking for something to throw in there that I will not have to worry about, even hooking hard with some slicks at the drag strip.

I will look at a stock replacement VS someone rebuilding the one I have.

murphinator

iTrader: (2)

I agree with dannyz you only need to look as far as the best 60 foot on stock 10 bolt thread in this section to see plenty of positive results on some very quick cars on 7.5 10 bolts with automatics https://ls1tech.com/forums/gears-axl...ock-7-5-a.html

M6 is a 7.5 wrecker that is where most of the weak 7.5 legend comes from 2 different worlds between stick and auto.

Now I see a couple eyebrow raisers in your planned build/mods... 500 whp naturally aspirated is going to take some serious cubes , some serious compression or both , of course serious compression is going to take either race fuel or an e85 conversion.

2500 stall is not going to work well with the type of cam you will need to get to 500whp , you will need a bigger stall , do you have any components chosen yet for your build ? lots of people on here that can help you pick the right parts to assure success on your build so share your plans and ask for input before you spend $$.

You mentioned the Hawks 8.8, I would contact BMR they just dropped a big hint in the 8.5 10 bolt thread on here that they may be developing a fabricated 8.8 housing (page 4 post 61) which is very exciting with all the cheap 8.8 parts out there from explorer , ranger , mustang ,etc... plentiful junkyard parts to build a stout 8.8 if they develop a bolt in housing.

https://ls1tech.com/forums/gears-axl...es-we-can.html

01ssreda4

iTrader: (96)

Wouldnt buy **** from Hawks.....that being said, I know the 9 inch stamped version typically requires clearancing to the drive tunnel. Fab9 would be my choice if budget was no concern. If budget IS a concern I think Id lean towards a 12 bolt or s60 from Strange. You could probably get into an s60 for slightly cheaper and its a stronger (bigger) rear end then a 12 bolt but both should fit like stock. That being said Im running a 12 bolt and have been happy so far, my main complaint is not going with a 9 inch just for ease of swapping gears, due to the fact that I do stupid stuff like that often. Here's my write up if youre interested.

https://ls1tech.com/forums/gears-axl...t-install.html

Carl at CRP

iTrader: (9)

There are several potential solutions for Your situation, many have the ability to take Your drivetrain to the next level, some are a bit of a roll of the dice. Whichever You decide on do Your self a favor and look at the history of the sponsor You are thinking of doing business with. You can click on this link and look in the top right corner where it says "Search this Forum" then type the sponsor's company name to see what their history is. https://ls1tech.com/forums/ls1tech-sponsor-feedback-70/

If You have questions I can answer for You please call 316-299-8427 or message Me here on LS1Tech.

Good luck on Your decision because its getting ready to be a sponsor fest in Your thread.

Carl Loder
Owner and head janitor of CRP

bunkerbuster

Thanks everyone for the replies.

murphinator - you are right, 500 is alot. It was a HP figure with some head room built in for the sake of picking a reliable rear end. Realistically, we are expecting 1.5HP/ci on a 6.2L (376).

Here is what I have already spent $ on:
-Machine Shop work for LS3 and L92 heads (fix valve seals, freshen, turn crank ordered bearings to match turned crank, line honed, decked block)
-BTR LS3 N/A Stage 4 Cam
-BTR Pushrods
-Unknown Springs (definitely aftermarket), machine shop checked spring rate as OK for cam
-GM crank timing gear, cam timing gear, spacer for chain
-katech C5r chain
-BTR trunion kit
-Extreme Automatics 4L60e Stage 3

Everything else is assumed stock except lowering springs. Right now, I am just building my list and checking it twice. The UMI stuff has yet to be ordered.

FirstYrLS1Z

iTrader: (4)

Definitely do not do a stall below 3500.

ssvert99

iTrader: (26)

Build the 10 bolt, it will live fine for your build. Put the money toward good parts for your drivetrain, like a better driveshaft and a high quality stall converter in the 3600-4k range. A properly built 10 bolt will hold on for a long time if you don't abuse it.

We would be happy to help you out on the project and give you real world experience as we have a ton of customers like yourself and do the same thing right here in our shop.

jhshnh

A Strange 12 bolt could be fine for what you're looking, or an S60. They're right at the price of a Hawks 8.8, and I would always choose a purpose built rear end from Strange over the 8.8, especially seeing the cost is close to the same.

MidwestChassis2

iTrader: (1)

To put it simple you have to look at what you are getting for what you are spending, secondly you have to look at who you are purchasing from for a life time of advice from a very long time of experience from utilizing the products they manufacture.

You will read that our fabricated housing bolts in just like the factory 10-bolt came out and no other rear end on the market can say this. We have done multiple installs of our own product and because of this we know what to do to make the install as simple as possible. Not only by giving certain options standard but supplying you with all the needed hardware.

Like ssvert99 already stated the 10-bolt may live up to your needs but if it doesn't give us a call and we can discuss multiple different options. If you can't afford a the entire purchase up front that isn't a problem as we allow layaway on all our products. We understand how expensive our hobby is.