C20 Rear End Ratios? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Texasdeere · 01-08-2008, 03:55 PM

I am picking up a 64 C20 with a 283/Powerglide soon.

I was wondering what kind of rear end gears the 60-66 3/4 ton trucks came with. The truck has the round diff cover, so maybe it is an Eaton?

Thanks

kris's66lwb · 01-08-2008, 04:59 PM

yea ihave the same onein my 65 k20 and there real low dont plan on goning over 65 if you find gears for them let me know

greg64 · 01-09-2008, 05:16 PM

Hey TexasC10, have a look at http://www.6066gmcguy.org/DriveAxle.htm

It might give you an idea what you have.

Greg

brawley · 01-09-2008, 06:10 PM

I believe I saw a round 3/4 ton trucks rear end kit in LMC truck.

kris's66lwb · 01-09-2008, 06:28 PM

cool il look there was it in the catilog

Texasdeere · 01-10-2008, 06:50 AM

I read they came with 4.10 or 4.56 gears. Gary's Gears (I think) used to sell a 3.90 a few years ago. (Still too low for me) I'll check the LMC catalog too.

If that is what this truck has in it I will install a 700R4 set up with the stock engine. With the lock up that should be around 2100 w/4.10 gears to 2400 w/4.56 gears at 65.

kris's66lwb · 01-10-2008, 01:18 PM

i looked in the lmc and no ring and pinions for it the have every thing but

Fred T · 01-10-2008, 04:52 PM

Art Houser was cutting gears for the HO52 differential, but he died a couple of years ago. Most of the gears for this rear were 4.56. There were some 4.10s. I have heard of only one set of 3.90 that were factory, which will give you an idea as to how rare they are.

In reality, you have two decent options. One is to go the 700R4 route. The other is to swap out the rear for a later 14 bolt full floater. 3.77 is real common, there are even a few 3.42.

kris's66lwb · 01-11-2008, 03:27 PM

no go for the 700r4 and prob not on the 14bolt

Texasdeere · 01-11-2008, 03:58 PM

This place has crossmembers and everything else you need to do the swap. The transmissions are usually $600 to $900+

http://www.bowtieoverdrives.com/index.shtml

kris's66lwb · 01-11-2008, 04:01 PM

its no the brakets and stuff i just dont want it i love my 350

01-08-2008, 03:55 PM	#1
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	C20 Rear End Ratios? I am picking up a 64 C20 with a 283/Powerglide soon. I was wondering what kind of rear end gears the 60-66 3/4 ton trucks came with. The truck has the round diff cover, so maybe it is an Eaton? Thanks

01-08-2008, 04:59 PM	#2
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: C20 Rear End Ratios? yea ihave the same onein my 65 k20 and there real low dont plan on goning over 65 if you find gears for them let me know

01-09-2008, 05:16 PM	#3
greg64 Registered User Join Date: Dec 2007 Location: Kimberley, BC, Canada Posts: 799	Re: C20 Rear End Ratios? Hey TexasC10, have a look at http://www.6066gmcguy.org/DriveAxle.htm It might give you an idea what you have. Greg

01-09-2008, 06:10 PM	#4
brawley Easy Does It Join Date: Apr 2007 Location: Dirdy Mo , North Carolina Posts: 450	Re: C20 Rear End Ratios? I believe I saw a round 3/4 ton trucks rear end kit in LMC truck.

01-09-2008, 06:28 PM	#5
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: C20 Rear End Ratios? cool il look there was it in the catilog

01-10-2008, 06:50 AM	#6
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	Re: C20 Rear End Ratios? I read they came with 4.10 or 4.56 gears. Gary's Gears (I think) used to sell a 3.90 a few years ago. (Still too low for me) I'll check the LMC catalog too. If that is what this truck has in it I will install a 700R4 set up with the stock engine. With the lock up that should be around 2100 w/4.10 gears to 2400 w/4.56 gears at 65. Last edited by Texasdeere; 01-10-2008 at 06:54 AM.

01-10-2008, 01:18 PM	#7
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: C20 Rear End Ratios? i looked in the lmc and no ring and pinions for it the have every thing but

01-10-2008, 04:52 PM	#8
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Re: C20 Rear End Ratios? Art Houser was cutting gears for the HO52 differential, but he died a couple of years ago. Most of the gears for this rear were 4.56. There were some 4.10s. I have heard of only one set of 3.90 that were factory, which will give you an idea as to how rare they are. In reality, you have two decent options. One is to go the 700R4 route. The other is to swap out the rear for a later 14 bolt full floater. 3.77 is real common, there are even a few 3.42. __________________ Fred There is no such thing as too much cam...just not enough engine.

01-11-2008, 03:27 PM	#9
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: C20 Rear End Ratios? no go for the 700r4 and prob not on the 14bolt

01-11-2008, 03:58 PM	#10
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	Re: C20 Rear End Ratios? This place has crossmembers and everything else you need to do the swap. The transmissions are usually $600 to $900+ http://www.bowtieoverdrives.com/index.shtml

01-11-2008, 04:01 PM	#11
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: C20 Rear End Ratios? its no the brakets and stuff i just dont want it i love my 350



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