68 Rear Diff. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68ChevyGuy · 08-07-2008, 08:09 PM

Anyone know what the stock gear ratio on a 68 Chevy C20 8lug rear diff is ? I heard from a few guys 4.11, which is some what hard to believe and far as I know, its the original rear end too.

LONGHAIR · 08-07-2008, 08:13 PM

Transmission: Automatic or Stick?

68ChevyGuy · 08-07-2008, 08:15 PM

Originally was a manually, with a sb320.. I converted it to a TH350 and a 71-73 sb350

haysonj · 08-07-2008, 08:34 PM

My 69 k20 4x4 had 4.09 gears front and back

Longhorn Man · 08-07-2008, 09:01 PM

what engine was in there originally?
4.09 gears.... is that listed on the SPID? I have never heard of that in a stock truck

**Classic Bowties** · 08-08-2008, 01:56 AM

Quote:

Originally Posted by Longhorn Man

what engine was in there originally?
4.09 gears.... is that listed on the SPID? I have never heard of that in a stock truck

Its a K series deal as I have seen several original 20's that have had one of those small oe type metal Id tags (stamped 4.09) hanging from a diff. cover bolt on their front 44's, I am pretty sure I have a 71 K20 in the yard that is still wearing that tag, and if so I can get a pic. in the am. I am thinking if marked with the 4.09 tag up front then they left the factory with 4.10's out back, IIRC.

stllookn · 08-08-2008, 02:26 AM

C20 standard was 4.57, Longhorn was 4.57, C20 panels and subs were 4.57, K20 front was 4.55...rear 4.57, K20 panels and subs were the same as K20 pickup. The 396 option got a standard 3.54 Dana. 4.56 Dana was used with the optional leaf spring rear suspension option on other displacement options. At least that is what the 1968 GM Restoration Guide states.

4.10 ratio appears to be the only C20 optional rear axle ratio and it was not offered for the 396. The big block only came with a 3.54. There were no optional ratios with the K20's either in '68. Other years are probably different.

68ChevyGuy · 08-08-2008, 02:40 AM

Thanks for the info, big help!

haysonj · 08-08-2008, 08:31 AM

Quote:

Originally Posted by Longhorn Man

what engine was in there originally?
4.09 gears.... is that listed on the SPID? I have never heard of that in a stock truck

I probably should not have responded to his post as my truck is a morph. It does have a tag on the front Dana 44 that reads 4.09 and I changed the rear end so I could match the front. the spid in the original cab was painted over but the truck had a 350 in it when I bought it.

08-07-2008, 08:09 PM	#1
68ChevyGuy Registered User Join Date: Aug 2008 Location: MT and SD Posts: 16	68 Rear Diff. Anyone know what the stock gear ratio on a 68 Chevy C20 8lug rear diff is ? I heard from a few guys 4.11, which is some what hard to believe and far as I know, its the original rear end too. __________________ 1968 Chevy C20 357/350 May the crabs of a thousand Las Vegas hookers infest the crotch of the person who fu<ks up your day, and may their arms be to short to scratch.

08-07-2008, 08:13 PM	#2
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: 68 Rear Diff. Transmission: Automatic or Stick?

08-07-2008, 08:15 PM	#3
68ChevyGuy Registered User Join Date: Aug 2008 Location: MT and SD Posts: 16	Re: 68 Rear Diff. Originally was a manually, with a sb320.. I converted it to a TH350 and a 71-73 sb350 __________________ 1968 Chevy C20 357/350 May the crabs of a thousand Las Vegas hookers infest the crotch of the person who fu<ks up your day, and may their arms be to short to scratch.

08-07-2008, 08:34 PM	#4
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: 68 Rear Diff. My 69 k20 4x4 had 4.09 gears front and back __________________ 69 Chevy 4x4 383 Power

08-07-2008, 09:01 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 68 Rear Diff. what engine was in there originally? 4.09 gears.... is that listed on the SPID? I have never heard of that in a stock truck

08-08-2008, 02:26 AM	#7
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: 68 Rear Diff. C20 standard was 4.57, Longhorn was 4.57, C20 panels and subs were 4.57, K20 front was 4.55...rear 4.57, K20 panels and subs were the same as K20 pickup. The 396 option got a standard 3.54 Dana. 4.56 Dana was used with the optional leaf spring rear suspension option on other displacement options. At least that is what the 1968 GM Restoration Guide states. 4.10 ratio appears to be the only C20 optional rear axle ratio and it was not offered for the 396. The big block only came with a 3.54. There were no optional ratios with the K20's either in '68. Other years are probably different. __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary) Last edited by stllookn; 08-08-2008 at 02:36 AM.

08-08-2008, 02:40 AM	#8
68ChevyGuy Registered User Join Date: Aug 2008 Location: MT and SD Posts: 16	Re: 68 Rear Diff. Thanks for the info, big help! __________________ 1968 Chevy C20 357/350 May the crabs of a thousand Las Vegas hookers infest the crotch of the person who fu<ks up your day, and may their arms be to short to scratch.

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