Anyone ever adapt a Ford 8.8 IRS to a C3?

1981Z06Vette

1981Z06Vette

Well-known member
Joined
Apr 8, 2008
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89
Location
Woodstock, GA
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
 
Post some pix of the 8.8 and some dimensions....kinda curious what ratios they come in too.....

:eek::thumbs:
 
mrvette said:
Post some pix of the 8.8 and some dimensions....kinda curious what ratios they come in too.....

:eek::thumbs:
Click to expand...

The earlier ones are going to mostly be 2.73s or 3.27s, but I'm pretty sure the later ones (Cobra) had more gear. Motorsport gearsets are cheap compared to the good Vette stuff, and available anywhere. 2.73, 3.08, 3.27, 3.55, 3.73, 4.10 , 4.30, 4.56...pretty good selection.Not sure if the posis (Traction-Lock) are the same as non-IRS, I found some listings for an IRS posi on Ebay.
 
1981Z06Vette said:
mrvette said:
Post some pix of the 8.8 and some dimensions....kinda curious what ratios they come in too.....

:eek::thumbs:
Click to expand...

The earlier ones are going to mostly be 2.73s or 3.27s, but I'm pretty sure the later ones (Cobra) had more gear. Motorsport gearsets are cheap compared to the good Vette stuff, and available anywhere. 2.73, 3.08, 3.27, 3.55, 3.73, 4.10 , 4.30, 4.56...pretty good selection.Not sure if the posis (Traction-Lock) are the same as non-IRS, I found some listings for an IRS posi on Ebay.
Click to expand...

eh, I forgot about that posi aspect, every RWD car I have ever had for some 45 years of ownership now, has had posi.....can't imagine a car without it....even my old work truck.....

:D 308 is a good choice today if you have an auto, if stick, well, a 5 speed and 355 ish is good....but need overdrive for economy what with gas being so stupid these daze....

:crutches:
 
I'm going 4.10, but only because I am using a T56 with a .50 overdrive, and that will give me a very good mix of performance and fuel economy (my much heavier 97 SS got over 25mpg with that combination, with an engine with far less torque). 2300 rpms at 85mph! :thumbs:
 
1981Z06Vette said:
I'm going 4.10, but only because I am using a T56 with a .50 overdrive, and that will give me a very good mix of performance and fuel economy (my much heavier 97 SS got over 25mpg with that combination, with an engine with far less torque). 2300 rpms at 85mph! :thumbs:
Click to expand...

I have a 336 and 200 4r auto in my '72, and turn about the same it gets 22.222 mpg at 90 mph...not too bad....24 if I back off a bit down to 60-70....

not so awful evil....that 6 speed does make stiffer gears ok to live with though.....I still would limit it to 373, IMO, anyway....

:bounce::nuts:
 
Twin_Turbo said:
GEE crammed an 8.8 in his miata :)
Click to expand...

Hey Marck , The first unit we used for mockup was a cast iron hsg from a super coupe 3:55 ratio . Later picked up a lincoln alloy hsg and switched out the spool etc from the sc as it is a posi . These are quite robust units and would be no problem for a swap into a c3 . I posted a pic of the miata in the hill climb thread ,,,,,,,,,, had to have the wheels made to fit the big tires .

GEE
 
HUMMMM.....another project?? perhaps.....

another sink hole for money....I could probably sell the vette parts for the costs involved though....

wonder how long this would take, and what mods are necessary to my frame....

can't weld here at my house, presently, I would have to put in a outlet, no problem got a left over 50 amp circuit @220 from a old hot tub....

plenty of cable....hummm....

:eek::fishing::suicide:
 
1981Z06Vette said:
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
Click to expand...

Darlene has a 95 T-bird. Done some work on the IRS -bearing. It is a very strong looking unit. I actually thought the same thing about what it would take to use on a C2/C3. After looking it over, it seemed to much work to adapt the whole thing. Never tought of just the center section.:huh:
 
glenn64vette said:
1981Z06Vette said:
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
Click to expand...

Darlene has a 95 T-bird. Done some work on the IRS -bearing. It is a very strong looking unit. I actually thought the same thing about what it would take to use on a C2/C3. After looking it over, it seemed to much work to adapt the whole thing. Never tought of just the center section.:huh:
Click to expand...

I am happy enough for my use with the stock 336 rear, so the whole Kahuna or nothing for me, but then I need weight and capability differences and what it brings to the table....:confused::drink:
 
mrvette said:
glenn64vette said:
1981Z06Vette said:
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
Click to expand...

Darlene has a 95 T-bird. Done some work on the IRS -bearing. It is a very strong looking unit. I actually thought the same thing about what it would take to use on a C2/C3. After looking it over, it seemed to much work to adapt the whole thing. Never tought of just the center section.:huh:
Click to expand...

I am happy enough for my use with the stock 336 rear, so the whole Kahuna or nothing for me, but then I need weight and capability differences and what it brings to the table....:confused::drink:
Click to expand...


Well, I think I saw some engineering specs on the NET at one time. Let me think on this.

When I was looking the T-bird IRS over, I was really impressed with it's design. It does use wish bone control arms. That is where the problem lies. :bump:
 
t_irs.jpg
 
glenn64vette said:
mrvette said:
glenn64vette said:
1981Z06Vette said:
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
Click to expand...

Darlene has a 95 T-bird. Done some work on the IRS -bearing. It is a very strong looking unit. I actually thought the same thing about what it would take to use on a C2/C3. After looking it over, it seemed to much work to adapt the whole thing. Never tought of just the center section.:huh:
Click to expand...

I am happy enough for my use with the stock 336 rear, so the whole Kahuna or nothing for me, but then I need weight and capability differences and what it brings to the table....:confused::drink:
Click to expand...


Well, I think I saw some engineering specs on the NET at one time. Let me think on this.

When I was looking the T-bird IRS over, I was really impressed with it's design. It does use wish bone control arms. That is where the problem lies. :bump:
Click to expand...


If I do this, I will just use the center section and maybe the CV shafts if that can be worked out...I would most likely use custom halfshafts. The biggest advantage would be strength over the stock C3 gearset, and I would imagine even an advantage over one of the 12 bolt conversions, since there wouldn't be any cutting or grinding of the case. Parts availability is also much better, either from the salvage yard, Ford Racing, or the aftermarket. I'll definitely pick one up on my next salvage yard venture.
 
1981Z06Vette said:
glenn64vette said:
mrvette said:
glenn64vette said:
1981Z06Vette said:
Rather than go to all the trouble and expense of a 12 bolt upgrade, why not adapt a readily available, modern IRS like the Ford 8.8? The Cobra units can be pricey from the salvage yards, but the T-bird units can be had pretty cheap, and there are tons of parts available for them. It couldn't be too hard to fab up a mount for it, and either mod the original CV shafts or adapt Vette type (aftermarket) half shafts for it. The 8.8 is every bit as strong as a 12 bolt, they're available and relatively cheap...I'm probably going to grab one the next time I hit the salvage yard.
Click to expand...

Darlene has a 95 T-bird. Done some work on the IRS -bearing. It is a very strong looking unit. I actually thought the same thing about what it would take to use on a C2/C3. After looking it over, it seemed to much work to adapt the whole thing. Never tought of just the center section.:huh:
Click to expand...

I am happy enough for my use with the stock 336 rear, so the whole Kahuna or nothing for me, but then I need weight and capability differences and what it brings to the table....:confused::drink:
Click to expand...


Well, I think I saw some engineering specs on the NET at one time. Let me think on this.

When I was looking the T-bird IRS over, I was really impressed with it's design. It does use wish bone control arms. That is where the problem lies. :bump:
Click to expand...


If I do this, I will just use the center section and maybe the CV shafts if that can be worked out...I would most likely use custom halfshafts. The biggest advantage would be strength over the stock C3 gearset, and I would imagine even an advantage over one of the 12 bolt conversions, since there wouldn't be any cutting or grinding of the case. Parts availability is also much better, either from the salvage yard, Ford Racing, or the aftermarket. I'll definitely pick one up on my next salvage yard venture.
Click to expand...

I'll be watching this. Darlene told me if I buy her a NEW Camaro she'll give me the T-bird.:eek:

It's a salvaged title.:skeptic:
 
A couple of questions...............

Is the 8.8 really more durable than the C3 diff or just more available? What would it take to convert the CV axle setup to U-joints axles?
 
BBShark said:
A couple of questions...............

Is the 8.8 really more durable than the C3 diff or just more available? What would it take to convert the CV axle setup to U-joints axles?
Click to expand...


If I remember correctly, that should not be a problem. The CV/axle bolts to the stub flange on the center section. I'll crawl under the Bird tonight and look at it. I MAY be able to get a picture. But I won't be able to get the pic on here till monday or tuesday.
 
Here is a pic of of an 8.8 with custom half shaft installed in a buickv8 powered miata .The cv joint from a super coupe with custom mosler axles . Taurus boots to clear tein suspension . The joints work well with a 2100 lb car .


GEE
 

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Another shot
 

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We got a couple of FORD boys here. Put the 8.8 question to them. They were all over it. Yes, the 8.8 is stronger than a 12 bolt and as strong (at least ) as a Ford 9 inch. This is looking better every second. :yahoo:
 
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