The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Best 12-bolt Posi Unit?

AirMale · 04-02-2003, 03:51 PM

Auburn-->good
Eaton--->best
3spd auto---->3.42 street
4spd auto---->3.73 street

I reccommend a series 3 Eaton posi. You can get a 3.73 gear to fit a 3 but a series 4 can only run 3.73 and up. So if you go with a #3 and 3.42's and you want more you can go up to 3.73's. A #4 will not accept anything lower than a 3.73. Check Ebay...type in 12 bolt you'll see a total Eaton posi, choice of gears and everything you need to fully rebuid your 12 for $559. NO randy's can't beat this, I called.

04-02-2003, 03:51 PM	#7
AirMale Senior Member Join Date: Jan 2003 Location: Atlantic City, NJ Posts: 1,073	Auburn-->good Eaton--->best 3spd auto---->3.42 street 4spd auto---->3.73 street I reccommend a series 3 Eaton posi. You can get a 3.73 gear to fit a 3 but a series 4 can only run 3.73 and up. So if you go with a #3 and 3.42's and you want more you can go up to 3.73's. A #4 will not accept anything lower than a 3.73. Check Ebay...type in 12 bolt you'll see a total Eaton posi, choice of gears and everything you need to fully rebuid your 12 for $559. NO randy's can't beat this, I called. __________________ 86 SWB 9.0 LITER T-400-OD 4.11 eaton-4/5 drop Best 1/4 12.51 @112mph no traction