I have a V6 Grand Prix and was wondering what rear differential is in the car as I was going to upgrade the ring and pinion, or possibly install a posi carrier. Do the V6 cars have the 7.5 (10 bolt) housings? Is 3.42:1 gear set too low? The car currently as 2.73:1 in it.
'85 Pontiac Grand Prix 3.8 Differential Size and Rear Gear Swap?
- Thread starter Shinobi68
- Start date
Yes, a n/a 3.8 v6 would come with a 7.5 10 bolt stock. Highest I recall seeing the factory run is a 3.08 in any of the cars if bought and sold through the years, but, that doesn't restrict you.
Depending on your location, I've got a non-posi 3.73 7.625 rear from a monte ss that would bolt right in, complete drum to drum even including the control arms. If youre close enough to coastal georgia, might be able to work out a deal on it.
Also have some performance 4bbl intake manifolds for the buick 3.8. Same story though, generally don't ship heavy stuff like that.
What are your intentions for this car? I wouldn’t run 3.73s w no over drive but you never said you don’t? My cabby is the truck in the family that hardly gets driven. Having 3.73s and my th200 would annoy me but like I said it’s not my daily. 2.73s aren’t unheard of but my understanding its not a common factory option but who knows what has been done in the past 30+ years…
Last edited:
Pretty far. I mean, I've driven to New Orleans to catch a Mardi Gras parade in the afternoon in the time since I moved away back around '09 when meant dropping to the gulf coast and heading west, but, I've also driven many a time from here to New England straight through, and, from New England to Las Vegas and back with only one hotel stop so that's not saying much. Did Memphis to here straight through not long ago too.
You 'could' probably make it headed down i20 then dropping to the coast, I'd guess 10-12 hours each way depending on the degree of weather and traffic. But it'd certainly be a haul and I'm sure you could source something closer.
For any actual board member (not a guy joining with 1 post just to buy something) I try to give breaks off what I'd otherwise ask if I advertised it or had gone to a swap meet.
So, I'd knock it down to $350, but, can't crate, can't ship. Honestly just too much life happening, it's not a question of extra money to make it worthwhile, its a physically can't be doing all that right now.
Brakes in it worked stopping the car off the trailer, and, they're all still there. Kept bags over the ends and drums for rain protection, and it's been stored on blocks. My helper cutting up the body nicked the ebrake cable so at that point we just cut it, not safe to be using one with some parted wires so it needed replacing anyways.
Before, well, life, I was going to pair it with a buick 350 into an 83 I really wanted to throw together this summer. Now it's just a plain spare part again.
Thanks for the reply. I’m not on here much, we have several g body projects..
I’d be down for a weekend road trip. I have a 3:08 but with the 406 on the way I need more gear. I’m committed to car shows the next 2 weekends but after that I can drive down.. let me know..
Thanks for the offer and the information. I have to check the code but they might actually be the 2.43 and I mistakenly said 2.73. If I'm reading correctly beginning with 3.42, require a different carrier(?). So I would need a different carrier to go with 3.42 or 3.73, I was just looking on Summit at the posi gear sets, and ring and pinions. Looks like I can pick up a new 28 spline gear set with 28 spline axles from Quick Performance, and or Moser.
I'm doing an LS1 swap out of a 2004 Vette with a 4L60E transmission. Stock it's 350/350 hp/tq. My intention for the car is to use it as a daily driver or as a grocery getter, just wanted something with good power, reliable, and get's good mpg. I thought maybe dropping gears into would be fun, as on one of my C5 cars (manual transmission) I had dropped in some 4.10s once and it was really fun getting the jump on other cars, even with just 350hp.
Last edited:
Similar threads
