Fox T-Bird/Cougar Forums

Technical => Drivetrain Tech => Topic started by: 83tcbird on November 20, 2009, 08:05:42 AM

Title: 7.5 to 8.8 rear end swap
Post by: 83tcbird on November 20, 2009, 08:05:42 AM
I have an 83 tc I swapped out the 7.5 to a 8.8 out of a 93 stang. It went in nice bolted right in the only issue I have is the gearing killed the car my 7.5 had 3.54 and the 8.8 is 3.73  what should i be running to bring this bird back to life?
Title: 7.5 to 8.8 rear end swap
Post by: TurboCoupe50 on November 20, 2009, 09:04:54 AM
your original gear would have been a 3.45...

Well lesee, you added .28 to your rear ratio, but being the early TC have a 4.03 first gear ratio is now 15.03 vs 13.90 which means it's going to wind up faster in the gears(1st will be most noticeable)... If anything it should seem a little stronger, you sure it doesn't have other issues??? Say cam or iginition is retarded...

Any possibility the new rear is a maybe a 2.73 or 3.08??? Stock, a Stang 8.8" never had 3.73s from the factory...
Title: 7.5 to 8.8 rear end swap
Post by: 83tcbird on November 20, 2009, 09:18:20 AM
Ya I have the tag on my tool box def 3.73 ...1st winds up the fastest...it was fine till i put the rear end in nows its real doggy

yes the org gear was 3.45 typo error!!
Title: 7.5 to 8.8 rear end swap
Post by: TurboCoupe50 on November 20, 2009, 09:35:00 AM
If it has a tag that states it's a 3.73, then then I can't see it being a 8.8"... Stock 8.8" Stang rears ranged from 2.73 to 3.27(the 3.27s arn't very common)... The 4cyl had 3.45 & 3.73, 7.5" rears...

Only factory 8.8" I know of in a passenger car, was the '87-'88 Turbo Coupes with automatic, 5 speeds got 3.55s those years...
Title: 7.5 to 8.8 rear end swap
Post by: 83tcbird on November 20, 2009, 09:40:16 AM
OK I will try to clean it up more to verify it...its pretty rusty  I bet its the 2.73 gear...the .73 is clear its before that its really pitted and hard to see

  thanks
Title: 7.5 to 8.8 rear end swap
Post by: TurboCoupe50 on November 20, 2009, 09:49:18 AM
My 5.0 Stang had 2.73s... If that's what you have, 3.55 or 3.73 cogs would be fine...
Title: 7.5 to 8.8 rear end swap
Post by: 83tcbird on November 20, 2009, 10:57:33 AM
cool thanks im going to check this weekend
Title: 7.5 to 8.8 rear end swap
Post by: jandmmustangs on November 20, 2009, 12:13:06 PM
Dont always trust the tag.  Jack the car up (install jackstands). And do the old, mark the tire and mark the drive shaft and count the rotations
Title: 7.5 to 8.8 rear end swap
Post by: 83tcbird on November 20, 2009, 12:46:08 PM
thats a good idea too.  The stang I got it from had a bunch of work done to it b4 he wrecked it
Title: 7.5 to 8.8 rear end swap
Post by: Chooglin on November 20, 2009, 06:22:09 PM
Quote from: jandmmustangs;299510
Dont always trust the tag.  Jack the car up (install jackstands). And do the old, mark the tire and mark the drive shaft and count the rotations


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