Thread: IRS Advice Needed

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Hi gang,

I apologize if I'm in the wrong spot (I'd appreciate any pointers to the "right spot" if that's the case) but I'm looking for some advice on Independent Rear Suspension options.

First some background; I am building a 1953 Ford F100 pickup which I would like to put an IRS under. I currently have a Horton's Evolution II front end (Mustang II based, similar to Heidt's) which will be mated to a fully boxed custom frame. Power will come from a 400 hp (approx.) 5.8L EFI motor backed by an AOD trans. The truck will ride on 18" or 20" rims and will utilize air suspension at all four corners (separate bag and shock, not all-in-one units like Shockwaves). However, before I can go any further, I have to figure out what rearend to use and I'd prefer it to be an IRS but I don't want to spend the $4K or so that a Heidt's 9" IRS commands.

This is where you come in. Do you know of any cheaper alternatives that would work with the above combination? I am looking for good handling, and decent ride quality with 1/4 mile times being a distant third. Has anybody done the research into this that can pass their findings on to me? Any web sites that deal with this topic in some detail?

One option I am very interested in is the Thunderbird SC 8.8" IRS. Has anybody used this rearend and if so, how well did it work? Does anybody know how much hp/torque this IRS handles in stock trim? Are there any kits available for using this IRS in a hot rod or custom vehicle? Are tubular/custom A-arms available? Large disc brake kits? Air bag mounts/kits?

Any help would be greatly appreciated. Thanks in advance.

Glen Mead - SOCP Webmaster
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Southern Ontario Classic Pickups
http://www.socp.net
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53 effie,
I would consider a late model corvette 84 to 90. They are
one of the most reliable rears around. They are cheap and easy to
mount under a pickup. I have installed 3 corvette rears in three different rods and all of them were exellent performers. I have never put air suspension on one though. I'm sure it can be done.
There is tons of aftermarket products for this rear end. As far as the T-Bird rear I hear it is an exellent choice as well. Many guys use it and claim it is almost as strong as the ole' 9".
There are several custom truck publication that have many article on this subject. If you contact them they might be able to send you the old issues with these articles.
Good luck to you and I hope I have been a little helpful.

Cheers,
Crusty

I think I'd go with the Vette. Those T Bird rears are Utt-Buggly! If you cut away all the junk and made some trick bracketry you might just pull it off, but man! the word is Utt-bugly. They are pretty wide too.

I like the T Bird IRS, and have one for a new project just in the
planing stages. I have the whole clip with sub frame to allow
the entire thing to bolt up with 4 bolts. It is about 63" wide
hub to hub, but one company that make shorter alxes and upper and lower
control arms in 2 overall widths is factory five.
The Mark VIII has an aluminum diff housing and aluminum lower
control arms. Also any 8.8 posi will fit in the housing.
As far as ugly goes, just get your head into the coolness of
having any IRS in your car, and then look back at those solid
axle cars, and then tell me what you think is ugly.
Happy hunting
Paul

This guy is using T-Bird IRS and airsprings on his web project!

http://www.geocities.com/btrc_57301/37ford3.html

(click the 'next' button to see more!)

With coil overs both are going to ride the same. The Vette has larger brakes,a large selection of wheels & off sets, There is a large seletion of kit suppliers & IMHO it's nicer looking.

Richard,

See the "Brent--HELP" thread, apparently there's a server problem.

Techinspector1 - I have enjoyed reading your replies that are right -on.......as far as the Rolls its a Silver Shadow placed on a highly modified 1986 El Camino frame. I picked this frame to start with because it was the proper track. I made the following changes.
1. added 1 1/2" to the length of the frame.
2. connected the front & rear portion of the frame with 3"x5" retangular tubing.The tubing was added where the GM frame kicks out just aft of the rear wheels & forward of the rear wheels)
The outriggers were then cut off.
3. Used Global west upper control arms. This enabled me to run big GM rotors.
4Added a x-member
5.Used GM station wagon springs. The top of the rear spring perches had to be raised 3" to maintain ride ht.(the forward end of the 2 upper control arms had to also be raised 3" to maintain proper geometry. The lower front spring perchases were lowered 1".
6.Used a GM crate motor/700R4,Ford 9" with GM control arms(big Buick.
7.Interior redone(7 skins)
8.the RR wiring was removed & I wired it using GM color codes.
9. There was no room for a vacuum booster so I used a caddys hydroboost mounted under the floor.

The body required 3 mos of repair & I painted it black.

I had a back operation so my goal of having it done this mo have slipped. Probably another 4 mos. Since I was unable to do much on the car for several mos my wife told me to go buy a store bought car. So I bought a 2002 Z06 to play with while healing.........Don

VETTE. I.R.S. IS THE WAY TO GO. PROGRESSIVE AUTOMOTIVE.COM CAN HELP INSTALL A VETTE. IRS IN YOUR VEH.