Ford 8.8 swap?

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Ccrussell

Ccrussell

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Hello,
I am considering a 8.8 ford swap to replace my 7.25 rear differential.this is anticipation of doing a turbo on the existing 225 cu.in. Slant six. The car has a stock 904 transmission.Will this present a problem with the Ford's 3:73 gearing? Will i wind up spinning the slant six too fast?
Apparently all the limited slip fords are3:73.
Thanks for any input. This is a relatively budget minded project, so i would like to be satisfied with the results .Ie spending cash wisely.
Thanks for any thoughts
 
I take it you already have this 8.8? I guess if you already have it and the length will work out / axles brakes can be reused it makes financial sense. I would look for a Dana 60 rather than stuffing an 8.8 under a Mopar. As for 3.73's with a turbo shouldn't be much of an issue depending on tire size. You might be overall happier with something like a 3.23 gear for cruising - all depends on what you are wanting it to do??
 
An 8.8 is a great option. Plenty of them around with 3:73 posi and disc brakes. Friend picked on for hid dart. Paid $200 for it. That's only about $1800+ cheaper then a Dana 60. :)
 
abodyjoe said:
An 8.8 is a great option. Plenty of them around with 3:73 posi and disc brakes. Friend picked on for hid dart. Paid $200 for it. That's only about $1800+ cheaper then a Dana 60. :)
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That would buy you a nice bolt in S60. I have about $800-900 in my Dana 60 with new moser 35 spline axles / brakes / bearings and the housing work to put it under an A body.
 
I don't follow Ford much, so I don't know if or when they stopped using the 8.8. I am however fairly certain Moser is making new 8.8 housings.I guess there will be plenty to go around.
 
tnts72 said:
That would buy you a nice bolt in S60. I have about $800-900 in my Dana 60 with new moser 35 spline axles / brakes / bearings and the housing work to put it under an A body.
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??? what would buy a nice s60?? the $200 you can get a 8.8 for?
 
abodyjoe said:
An 8.8 is a great option. Plenty of them around with 3:73 posi and disc brakes. Friend picked on for hid dart. Paid $200 for it. That's only about $1800+ cheaper then a Dana 60. :)
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2k will put you real close to a fully loaded S60
 
I would expect 3.73s to put you around 3k at 70mph
I know there are calculators online, but it's a pain to search on my phone
 
just make sure you get one with a locker. the tag will say for 3l73 or 4l10 for example. if it doesnt have the L after the first number it will be an open diff
 
They are good units. They were actually designed off the GM 12 bolt.
 
I think the 94-98 Mustang GT axle would be your best bet. Most are probably 3.27...

There's one of those in Tom Kamman's purple valiant. Will have rear disk brakes and is centered up, so no need to cut them down.
 
Thanks for all the replies. No i havent purchased anything yet. Am liking the 8.8 option , essentially due to its cost, and durability. I am liking the mustang GT option even more.
While i would obviously like to keep this all mopar, cost overides that choice and Ford will be the way to go in this case. (I have been looking for an 8.25 with limited slip but have not found anything affordable )
 
I was quite pleased with the Ford 8.8 when I put it in a S10 with a 350 V8. Just remember you will need the drive shaft end to match the pinion yoke and maybe another short side shaft plus machining to make the differential center in the car. What is the rear axle length?
 
abodyjoe said:
Yes I know. That's why i clearly stated ( so I thought) twice that the 8.8 is about $1800 cheaper.
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An S60 is not a Dana 60. That's like comparing AFR heads to stockers and saying they are the same... I bought a 3.55 powerlok Dana for $100 on Craigslist, they are everywhere and they can be had cheaply. Dana 60 out of an old ford or dodge pickup trumps an 8.8 in terms of strength / reliability. I don't see a need for an S60 in anything short of a pro mod build, or just because someone wants to have one and say, look at that $2500 rearend... If the op has an 8.8 that will fit without doing a lot of work to it / axles sure it makes sense. If you are building one though, do it right the first time!
 
Ccrussell said:
Thanks for all the replies. No i havent purchased anything yet. Am liking the 8.8 option , essentially due to its cost, and durability. I am liking the mustang GT option even more.
While i would obviously like to keep this all mopar, cost overides that choice and Ford will be the way to go in this case. (I have been looking for an 8.25 with limited slip but have not found anything affordable )
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Just curious, what happens if the slant six lays down after the turbo is installed... Turbo small block mopar...? I lean towards over builds when it comes to the drivetrain. I put a Dana in a 318 car for my wife, reason being once she gets bored with a car running 8.50's I will get to build a 408 to replace the 318. It's all about "your" long term goals with the car. Will be interested to see how big a turbo you slap on the slant and how well it runs. I also thought about a small turbo on the 318 after a rebuild vs a 408... So I'll be watching this one, good luck sir:happy1:
 
I did this swap from a 7.25 to a 98 Explorer 8.8, in my 68 Dart. The 8.8 has 3.73 gears and the 7.25 had 3.23s. My speedometer was accurate at 60 mph before the swap. Now, in order to go 60, by gps the cars speedometer reads 84mph. I'm running 24 1/2"dia tires so the rpms are well above 3000.
The sticky 8.8 thread here explains everything youll need to do. Personaly, I think the gear ratio is to low and I'm going to re-gear it to 3.23. Either that or install an overdrive.
 
I remember hearing somewhere that turbo motors work best by torquing against taller gears (like 3.27s) for longer periods as opposed to revving fast and dropping RPMs (and boost) in quick succession like you would with lower gears like 3.73 or 4.10.Maybe a turbo expert could correct or confirm this but I'd look for on with the 3.27 ratio,especially with a long stroke slant 6.
 
If you don't already have a 8.8 another option that I think is the correct width is a 8.8 out of a 90's Ranger. My Pop has a 64 Rambler that someone installed a Ranger 8.8 in and I measured it and was surprised that is 56-1/2" wide flange to flange which is just 1/8" difference from our a-bodies. The driveshaft offset was 1-1/2" which is 1/4" difference from an a-body but on Pop's Rambler it doesn't vibrate and it calls for the same offset as an A-body Mopar. All you have to do is cut off the Ranger brackets and weld on a set of Mopar spring perches 43" center to center and slap it in.

Your tire height will have a great effect on the final drive ratio which determines the rpm your engine will spin down the highway. Here's a calculator that you can input all the values for your car and it'll tell you the rpm's it'll be spinning down the road

http://vexer.com/automotive-tools/speed-rpm-calculator
 
67GTConvert said:
I remember hearing somewhere that turbo motors work best by torquing against taller gears (like 3.27s) for longer periods as opposed to revving fast and dropping RPMs (and boost) in quick succession like you would with lower gears like 3.73 or 4.10.Maybe a turbo expert could correct or confirm this but I'd look for on with the 3.27 ratio,especially with a long stroke slant 6.
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I was going to mention that. ^

Bill Dedman and others have found that a turbo /6 works best with taller gears, even in the 2.xx range. It will build boost better in lower RPM's.

If money is tight, look for another 8.8 with a diffrent ratio so you don't have to do it twice.
 
Some Ford 8.8 info....

all ranger 8.8 axles are 28 spline and drum brakes
only some car(mustang) are 31 spline, most are 28.
all 95-01 Exploder axles are 31 spline and have disk brakes.
Axle shaft Dia is 1.32" Dana 60 axle shaft dia 1.40"
Axle ratios available from factory 2.73, 3.08, 3.27, 3.31, 3.56, 3.75, 4.10
Limited slip available in 3.31,3.56, 3.73 and 4.10
Yokes available in 3010 and 1350 u joints
You can get lots of aftermarket lockers for them.
If you want to compare D60 dont forget the extra HP required to spin the 60 which will also cost a few mpg as well.
an 8.8 will handle well over 450hp and lots of torque

We used them in Jeeps for years with zero failures, think 5000# wrangler 35-37" tires, 4.88 & 5.13 gears, 350-400 hp 4-1 low range then go play in huge boulders. I seriously doubt that a 3300# car with say 275 60 15 is going to ever get traction to match that.
If you cant find the right ratio w locker, then swap a locker into a 3.31. You should be able to get one for $100.

Get a 3.31 and put it in!!!!
 
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