Just looking for advice!!
Drifting
Joined: Oct 2024
Posts: 1,656
Likes: 383
From: Toronto, Ontario
Seriously though GTR1999 is the person to contact for a quality built differential. Good Luck!
Race Director
Joined: Nov 2006
Posts: 13,148
Likes: 7,761
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Have to agree, would be pretty hard to beat Gary for quality.
However, just to throw in another option, Bairs Corvettes.
However, just to throw in another option, Bairs Corvettes.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,013
Likes: 4,367
From: Marlton NJ
My 2 cents:
1. Gtr1989
2. yourself, Bairs, or Zip
3. anybody else
There is a Big quality jump between each step. Gary is the best in the world on these, now that Tom's service is gone.
With some guidance you can do the job as good as, or a better job, than anyone but Gary. Because you will be cautious and take your time.
https://www.corvetteforum.com/forums...iff-build.html
1. Gtr1989
2. yourself, Bairs, or Zip
3. anybody else
There is a Big quality jump between each step. Gary is the best in the world on these, now that Tom's service is gone.
With some guidance you can do the job as good as, or a better job, than anyone but Gary. Because you will be cautious and take your time.
https://www.corvetteforum.com/forums...iff-build.html
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,013
Likes: 4,367
From: Marlton NJ
I would not blame you for not wanting to learn how to do it yourself, it can be a little intimidating.
My next choice would be to contact GTR1989 by PM or email.
My next choice would be any of the 3 corvette shops near Delaware.
Bairs (Erie, Pa) , or Zip (Virginia) or Corvette Paramedics (Mt Holly, NJ).
Corvette Paramedics is the closest to you, maybe an 60-80 min away from you, and just down the road for me.
I know them well.
(search for corvetteparamedicsinc on facebook)
They specialize in service, and have done a lot of C3 work over the last 40 years.
They usually have 30 cars there, and half of them are C3s.
They do trailing arms in house and I know hold them to .001" clearance. They did mine.
They no longer do diffs in house, but the guy they send them out to is in the diff business, and has been doing C3 diffs for them for years and does a great job.
So he knows what makes IRS diffs different from regular ones. Many diff guys just think they know.
One of the biggest issues you will have on a 78 is the softer axles, they may be shot and need replaced. They can be worn out in as little as 60k miles.
If you can pull the diff, or even just the half-shafts, you can check that yourself pretty easily.
Grab the h/s yoke coming out of the diff and yank on it, back n forth. There should be very little movement.
Once it gets up to around .100" or 1/8" movement, the faces are pretty worn, and you are most likely going to need new diff yokes.
If that is the case, sourcing good diff yokes will be the most challenging aspect of your diff build.
My next choice would be to contact GTR1989 by PM or email.
My next choice would be any of the 3 corvette shops near Delaware.
Bairs (Erie, Pa) , or Zip (Virginia) or Corvette Paramedics (Mt Holly, NJ).
Corvette Paramedics is the closest to you, maybe an 60-80 min away from you, and just down the road for me.
I know them well.
(search for corvetteparamedicsinc on facebook)
They specialize in service, and have done a lot of C3 work over the last 40 years.
They usually have 30 cars there, and half of them are C3s.
They do trailing arms in house and I know hold them to .001" clearance. They did mine.
They no longer do diffs in house, but the guy they send them out to is in the diff business, and has been doing C3 diffs for them for years and does a great job.
So he knows what makes IRS diffs different from regular ones. Many diff guys just think they know.
One of the biggest issues you will have on a 78 is the softer axles, they may be shot and need replaced. They can be worn out in as little as 60k miles.
If you can pull the diff, or even just the half-shafts, you can check that yourself pretty easily.
Grab the h/s yoke coming out of the diff and yank on it, back n forth. There should be very little movement.
Once it gets up to around .100" or 1/8" movement, the faces are pretty worn, and you are most likely going to need new diff yokes.
If that is the case, sourcing good diff yokes will be the most challenging aspect of your diff build.
Last edited by leigh1322; Nov 18, 2024 at 10:18 AM.