78 rear axle ratio ?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

solidaxel · 09-09-2013, 04:26 PM

I am trying to prove the rear axle ratio on my 78 1/2ton Silverado with out taking off the rear cover

the numbers on the pass/ side tube are KAS 229 W 8S

This is a stock 350 Auto that i have had since 78 and the numbers are not in the glove box that says anything about the rear axle ratio.

Ehere can I find this info, as I need it for the programmer on the LS computer!

Thanks Folks

tlawre87 · 09-09-2013, 04:57 PM

Count the number of times the drive shaft spins to the rear wheel (jacked up of course)

Keith Seymore · 09-09-2013, 05:09 PM

Per the info packet in the GM Heritage Center archives (page 15 of the pdf; page 12 of the original):

http://www.gmheritagecenter.com/docs...olet-Truck.pdf

base axle is a 3.07. That assumes no one has changed it.

If you had an optional axle ratio it would appear on the SPID label.

K

solidaxel · 09-09-2013, 05:23 PM

It is not posi-trac!

solidaxel · 09-09-2013, 05:29 PM

Thanks, after many tests rotations, I think the 3:07 is accurate.

THANKS

solidaxel · 09-09-2013, 05:35 PM

After reading the Heartiage center doc. it said that a Heay Half, which is what this is, it says that it is a 3:40 !

solidaxel · 09-09-2013, 05:42 PM

The computer is programed fpt the 3:40 - 1, I guess i will live with this decision !!!

Thanks for the info

09-09-2013, 04:26 PM	#1
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	78 rear axle ratio ?? I am trying to prove the rear axle ratio on my 78 1/2ton Silverado with out taking off the rear cover the numbers on the pass/ side tube are KAS 229 W 8S This is a stock 350 Auto that i have had since 78 and the numbers are not in the glove box that says anything about the rear axle ratio. Ehere can I find this info, as I need it for the programmer on the LS computer! Thanks Folks __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

09-09-2013, 04:57 PM	#2
tlawre87 Registered User Join Date: Jun 2012 Location: Meeker, ok Posts: 146	Re: 78 rear axle ratio ?? Count the number of times the drive shaft spins to the rear wheel (jacked up of course) __________________ Trevor 74 C20...work in progress. 04 Saturn Ion...Daily Driver

09-09-2013, 05:09 PM	#3
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,287	Re: 78 rear axle ratio ?? Per the info packet in the GM Heritage Center archives (page 15 of the pdf; page 12 of the original): http://www.gmheritagecenter.com/docs...olet-Truck.pdf base axle is a 3.07. That assumes no one has changed it. If you had an optional axle ratio it would appear on the SPID label. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

09-09-2013, 05:23 PM	#4
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: 78 rear axle ratio ?? It is not posi-trac! __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

09-09-2013, 05:29 PM	#5
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: 78 rear axle ratio ?? Thanks, after many tests rotations, I think the 3:07 is accurate. THANKS __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

09-09-2013, 05:35 PM	#6
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: 78 rear axle ratio ?? After reading the Heartiage center doc. it said that a Heay Half, which is what this is, it says that it is a 3:40 ! __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

09-09-2013, 05:42 PM	#7
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: 78 rear axle ratio ?? The computer is programed fpt the 3:40 - 1, I guess i will live with this decision !!! Thanks for the info __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

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