8.5" 10 bolt spline count - The 1947 - Present Chevrolet & GMC Truck Message Board Network

swb85 · 11-16-2007, 04:03 PM

What year did the 8.5" 10 bolt switch from 28 spline axles to 30 spline? I know it was sometime in the 80's, but no idea what year. I need to know what my '85 came with.....it's about time for a locker.

jimfulco · 11-17-2007, 10:28 PM

An '85 would have come with 28-spline axles. The 30's didn't show up until '88 or '89.

Duro5341 · 11-17-2007, 10:33 PM

my 86 had 28 spline, I upgraded to the 30 spline when I rebuilt it.

Duro

swb85 · 11-18-2007, 09:44 AM

Sweet, thanks guys!

454c20 · 11-18-2007, 12:29 PM

Quote:

Originally Posted by Duro5341

my 86 had 28 spline, I upgraded to the 30 spline when I rebuilt it.

Duro

Did you go with aftermarket 30 spline axles or factory? I have a good 30 spline 8.5" posi unit in my basement and would like to put it in my 87 1/2 ton. I'm thinking axle shafts from a 88-newer 30 spline 6 lug 8.5" would work. Can anyone confirm this?

Thanks
Nick

'83Sierra · 11-18-2007, 02:30 PM

I'm also wondering this. I have 3.73 gears from my 2001 silverado that i want to put into my 83 sierra. What would i have to change to make it work? Theyre both 10 bolt.

11-16-2007, 04:03 PM	#1
swb85 On a budget like Fred Sanford Join Date: Oct 2005 Location: Topeka, KS Posts: 2,031	8.5" 10 bolt spline count What year did the 8.5" 10 bolt switch from 28 spline axles to 30 spline? I know it was sometime in the 80's, but no idea what year. I need to know what my '85 came with.....it's about time for a locker. __________________ '85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD

11-17-2007, 10:28 PM	#2
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Re: 8.5" 10 bolt spline count An '85 would have come with 28-spline axles. The 30's didn't show up until '88 or '89.

11-17-2007, 10:33 PM	#3
Duro5341 Registered User Join Date: Dec 2006 Location: Earth Posts: 239	Re: 8.5" 10 bolt spline count my 86 had 28 spline, I upgraded to the 30 spline when I rebuilt it. Duro __________________ -1986 K10 LWB, 350 HD,TH400 3.08, 30 spline 10 bolt, with an Auburn Posi, 31" tires All original, second owner truck -1979 Monte Carlo, 350, 200r4, 3.73 posi -1987 GT T-top Mustang - slow moving project

11-18-2007, 09:44 AM	#4
swb85 On a budget like Fred Sanford Join Date: Oct 2005 Location: Topeka, KS Posts: 2,031	Re: 8.5" 10 bolt spline count Sweet, thanks guys! __________________ '85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD

11-18-2007, 02:30 PM	#6
'83Sierra Registered User Join Date: Oct 2007 Location: Edmonton, Alberta Posts: 26	Re: 8.5" 10 bolt spline count I'm also wondering this. I have 3.73 gears from my 2001 silverado that i want to put into my 83 sierra. What would i have to change to make it work? Theyre both 10 bolt. __________________ '01 Silverado ECSB 4x4 True Flow - Magnaflow - Black Bear Tune - 35" BFG A/T - 4.56 Auburn - DD / Thug Ride '83 Sierra RCSB 2wd 350 Under construction - Project



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