to all you guys who have done the swap i have a few questions i want to verify before sending my housing off.
my car is a 1990 base C4
installing a ford 8.8 rear
biggest tire would be a 15x10.5 ish
4 link with a panard is the plan at this point

Best i can tell my stock 1990 IRS rear end has the following measurements
1. hub to hub is 63.5"
2. offset 0.75" to the right

do these measurements sound correct? should i have them cut the housing to match the stock dimensions?
or:
1. hub to hub 62" this could allow for more wheel options?
2. do not off set the pinion, not sure how to handle this?

just looking for a little direction before i waste a housing lol.

thank you all for your input

 

When mine was completed it was measured from the pinion and overall width hub to hub (I do not remember the numbers as it was 10 years ago). Plumb bobs were used for all measurements. It was also narrowed 6 inches total (3" each side) as to fit deep dish wheels. I could go as wide as 12" wide. Currently have 17x11 with 315s. It is a 4 link with wishbone.

 

ok, so it sounds like if i narrowed it some it would not be an issue. i would like to still be able to run my stock wheels for street driving and run a 15 inch for drag racing so i am trying to figure out the offset game.

 

nice ride by the way!

 

If you want to used the stock offset-Then use the stock measurements for the housing.

 

Mine is 53 1/2" wheel to wheel. Tell whoever you are buying your parts from you want the housing centered, not the pinion centered. That should take care of the offset. I got all my parts thru S&W race cars. I had them weld the ends of the housing on , but leave the 4 link brackets loose. So I could get everything where I wanted it

 

Here's a couple more pics of how I did mine

 

that came out nice, so equal axle tubes on both sides then? also you said 53.5" is that a typo, 10 inches seems like a lot. not questing it obviously it works lol just surprised.

 

Before you settle on anything first see if you can find a set of 15" wheels with the same offset as your stock wheels. If you do then have the solid axle made the same width as stock. If you narrow it the factory wheels may no longer fit or you will wind up running a spacer to correct offset.

 

..... I had Moser supply the housing , axles , and brakes . And they did all the welding ... not cheap but beautiful . My housing is 62 1/2" wide axle flange to axle flange ... the rotors are an additional .200" thick each (62.9" overall) ... pinion centered ... the plan was to use the 15x10" Weld Pro Stars 6.5" back spacing that I already had . So the axles were drilled for 4 3/4" bolt circle ... the Ford 8.8 uses C-clips so you'll need new ends for your housing and you'll need to have your axles drilled for the GM bolt circle if you plan on using the stock wheels ... I also had a pair of Afco double adjustable coil over shocks that I needed to re-use $$$ so I mounted the shocks ahead of the axle . The brake kit is all new '96 Ford Explorer from Moser with park brake inside the rotor (same as my '87) . The 4 link stuff was matched to the rod ends that I had from a heim jointed trailing arm kit that was on the car . I did have to cut out a section of the compartment behind the drivers seat to clear the diff ... I scalloped the C-Beam and went up to the trans tunnel for the rear trans support instead of fabbing a crossmember ... that way there is no interference with the exhaust ... I went big with the slicks and put 28x11.50's on ... they do stick out but I also have a pair of Weld's 7.5" bs with M/T 315x60 drag radials that tuck under the wheel wells ..... The reason I went with Moser was two-fold ... first , their pricing was a little better than most and second , they have a 2-day turnaround ... I placed the order on a Thursday the week before Christmas and it was at my door in 4 large and heavy boxes on Christmas Eve exactly one week later .....

 

It is 53.5". That is the width it ended up being, so I could use the deepest dish 15x10 wheel I could find. I dont remember the offset.

 

Mine is 62" wide axel flange to axel flange. I ran the IRS for a long time and wanted to keep my rear wheels which are 15x10 with 6.5 backspace. 28x10.5s and 275 radials fit perfectly. I have a 9" housing from Quick Performance and Moser 35 spline axels.

Since you are doing the 8.8, be careful of what ends they graft on the axel tubes..... axel offset is different for different ends and some will limit your rear brake options.... which can be a problem with some offset and mfgrs wheels.... as some calipers won't clear the inner barrel of some wheels..... I myself dealt with this as my Billet Specalties Street Lite 6.5 BS wheels caused me some problems where only Wilwood (at the time) had a dedicated low profile caliper that fit and it sucked because it was only offered with a heavy street brake system. Luckily Strange Engineering now has low profile calipers which I just got a system with on my car and was able to knock some weight off it.... which is great but I nad to run those heavy Wilwoods for 5-6 yrs and now have bought 2 rear brake kits for the car.....

Good luck with your conversion. Here's my 84.





Will

 

thank you everyone for the information. seems like a 62 to 62.5 axle to axle may be where I need to be. with the brake rotors installed this would put me in the 62.4 - 62.9 range.

To address the C clip issue with the 8.8 i plan on installing for big ends (9" ford) which i believe will eliminate the c clip issue (please correct me if i am wrong lol)
I have access to stock 98 mustang brakes which i believe should clear 15 inch wheels. if not i may need to look at the moser kit.
I plan on having moser do all the housing setup as they are only 4 hours north of me. i will be putting new moser axles in it as well

what did you guys use for your 4 link spacing? i planned to measure this but i have not taken the stock IRS out yet.

Thank you again for the information

 

..... On my '87 I had the 4-link brackets set to 45" outside of bracket to outside of bracket with 7/8" spacing for the Heim Joints this worked out to 43 3/4" CLCL ... the shock mounting brackets were set at 39 1/2" CLCL to the front of the axle ... Your car is a '90 and there may be some differences (definitely to stock upper shock mounting) to my '87 so please verify dimensions BEFORE work starts ... FWIW ... I'm no 8.8 Ford expert but every one that I have encountered had 3 1/4" axle tubes ... most axle bracketry is made for 3" diameter tubes ... this might limit your choices and selection ... the Explorer calipers fit my 6 1/2" backspaced wheels but I had to grind a little off the outer corners for clearance to fit the 7 1/2's ... I never tried factory wheels .....

 

o yea i plan to measure everything before i start, i am just looking for some base line so i know about where i should end up. Thank you for mentioning the 3.25 tubes, i check and mine are for sure 3.25. I might just have Moser slide the 4 link brackets on and then i can get them positioned and welded myself.

the back spacing and trying to get stock wheels back on could be interesting. it would be nice to put the stock wheels on if i want to go cruse around. obviously i am looking at a axle swap so drag racing is taking more of a precedence lol