72 C20 rearend - The 1947 - Present Chevrolet & GMC Truck Message Board Network

z7199 · 04-06-2005, 05:11 PM

First I am new to this forum so hello to all, and thanks for all the help I know I will get. I have a 1972 Chevrolet C20 with the Big Block 402 it is a SCLB. I wanted to know what size rearends came in these trucks I know it probably varies alot but I have no idea at all. Would also like to know what gears and what if any kinda of Posi I can get for it. I am going to try to post pics hope this works!!

Also pics are at night so not real good and I have done some things since then also

Edmond · 04-06-2005, 05:18 PM

Welcome to the Board from the Netherlands!!
Great looking truck you got there, I like the color!! Looks like mine!!

Cya,
Edmond

Bill72BB · 04-06-2005, 05:21 PM

Welcome From So Cal.

Do you have Leaf or Coil springs in the rear ?
Most Leaf came with a Dana 60 ,3.54 stock many had 4.10 .

z7199 · 04-06-2005, 07:21 PM

Quote:

Originally Posted by Bill72BB

Welcome From So Cal.

Do you have Leaf or Coil springs in the rear ?
Most Leaf came with a Dana 60 ,3.54 stock many had 4.10 .

I do have the leafs in the rear and a 2 piece driveshaft if that matters. Also what is a good LSD for it I dont want a locker, and is there a code that will tell me on the glove box or in the VIN about the rear-end?

Bill72BB · 04-06-2005, 07:30 PM

If you don't show an option you probably have 3.54 , the option code for 4.10 was JA1 .

z7199 · 04-06-2005, 08:01 PM

Are the current option codes the same as they were in 72? Also what is the best way to make it a Posi/ Limited slip

**JIMs70GMC** · 04-06-2005, 09:24 PM

If it is a dana 60, then the factory limited slip, would be a powr-loc. I t was the max-traction option, can't remember the rpo right now.
Nice truck.
Welcome to the board!

z7199 · 04-06-2005, 09:39 PM

Quote:

Originally Posted by JIMs70GMC

If it is a dana 60, then the factory limited slip, would be a powr-loc. I t was the max-traction option, can't remember the rpo right now.
Nice truck.
Welcome to the board!

Well it's not the powr-loc I have the one wheel peel right now and it sucks, however I do think it is the dana 60 because of what I have heard before and the size of it. But how would I know if it was a dana 60 or not. Sorry to ask so many questions but I have no idea on this rear-end at all. and since this is the first forum I have found I have lots to ask.

Rod · 04-06-2005, 10:38 PM

option G87 was power- lok.

welcome to the boards.

As for what gear ratios available...being that you figure the truck was an original BB 402 truck it should have standard equipment 3.54 ratio rear dana 60 rear end. If there are no other listed option on the glove box sticker for options in regard to the rear end gears ratio, then it should have 3.54 if its a true original BB 402. It could have optional gears or 4.10 or even 4.56...but I myself have only seen 4.10 as an option with a BB 402. But any different gear ratio would have been identified on the glove box sticker if it's still readable.

Fred T · 04-06-2005, 10:43 PM

If it's the stock 10 bolt it will be either 4.54 or 4.10 gears. Best way to upgrade is to replace the entire differential with a 14 bolt. They are available in 3.73 and 3.42 in the full floater.

Trying to find better gears for a 3/4 ton differential is elusive, at best. The 4.10 gears are getting to be hard to find. Many of us with older 3/4 tons, like my 52, are happy to find the 4.10 gears, the entire pumpkin from the 64-72 swaps right into the older housing. Art Houser was cutting 4.10s at $600 a set, but he was recently lost in a car wreck, so you can't even buy them new. Randy's Ring & Pinion had some 3.90s cut a long time ago, but stopped production. Not many are willing to shell out that much money for a set of gears.

z7199 · 04-06-2005, 10:54 PM

Well it is the stock 10 bolt and to the best of my knowledge it is a true 3/4 ton with the BB 402 glove box says it is plus has 402 ci on the core support under the hood and emblems. So somebody would have to have done alot of work to make it look like a 3/4 ton BB 402. So Fred you think they got to be 4.10 or 4.56 okay knowing that were can I get a Limited Slip? Or is it still going to be easier to replace with a 14 bolt to get the LSD?

Rod · 04-06-2005, 11:19 PM

Trust me, it's 3.54 gears already if not optioned differently as per the glove box sticker.

You might find a power lok on ebay...maybe...but you have to find a 30 spline unit for your dana axles in this era if still a correct dana 60, 67-72 era.

If your rear axle looks like this style carrier then it's a dana 60..an older correct 67-72 one as it has ten bolts holding the cover on....count em there's ten bolts holding the cover. If its that shape but has 14 bolts holding the cover then the diffs been swapped already to a 14 bolt rear axle.

Rod · 04-06-2005, 11:26 PM

I have a dana 60 with 4.10 and the power lok and I have a dana 60 with 3.54 and no posi. Oddly enough there both from coil sprung rear 3/4 ton GMC's. I got some plans for them though, but can take pics if you want in some future time.

z7199 · 04-06-2005, 11:26 PM

Quote:

Originally Posted by Rod

If your rear axle looks like this style carrier then it's a dana 60..an older correct 67-72 one as it has ten bolts holding the cover on....count em there's ten bolts holding the cover. If its that shape but has 14 bolts holding the cover then the diffs been swapped already to a 14 bolt rear axle.

Yep looks just like that with 10 bolts so its a dana 60 30 spline with 3.56 or 4.10 is what I am getting and is e-bay going to be the only place to find that posi?

z7199 · 04-06-2005, 11:28 PM

Quote:

Originally Posted by Rod

I got some plans for them though, but can take pics if you want in some future time.

Yes the more info the better I like to see exactly what I am talking about. I would really like to see the 4.10 with power lok

Rod · 04-06-2005, 11:47 PM

You probably will hear of one hear one the board before ebay, a power lok posi 30 spline that is..they are are sought after units.

Fred T, I sent a 4.10 eaton diff with a detroit locker to a member here on the boards from Texas last month for his 1956 3/4 ton...weighed 142 pounds once crated up. Here's the pic. I heard about Art also... sad.

I post a pic of the eaton style diff so you can notice the difference also z7199.

The eaton diff come out the front as a unit...easy swap. Being yours is a dana ...not possible to do it like this. The dana gears are 3.54 not 3.56 as you said above.

Rod · 04-06-2005, 11:54 PM

Your basic dana 60 power lok Posi unit looks like this..this pic is of a correct 30 spline dana 60 power-lok which had 4.10's. Thats what you asked to see.

Rod · 04-07-2005, 12:19 AM

took all of about ten seconds to find one on ebay...but its up to you.

dana 60 powerlok 30 spline carrier unit auction link. http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WD1V

its not mine and I don't know the seller, buyer beware.

Should verify axle size also.

Chris H · 04-07-2005, 12:45 AM

Quote:

Originally Posted by z7199

Yes the more info the better I like to see exactly what I am talking about. I would really like to see the 4.10 with power lok

z7199,
Please fill out your profile so we know where you are located.

I have a complete Dana 60 4.10 leaf spring rear for 2wd, with the power lock.
I will take $300 for the complete rear end. Freight might be a killer depending on your location, but I would be willing to deliver or meet for gas money?
I can get pictures of it if you are interested.

Chris

04-06-2005, 05:11 PM	#1
z7199 Registered User Join Date: Apr 2005 Location: Houston TX Posts: 76	72 C20 rearend First I am new to this forum so hello to all, and thanks for all the help I know I will get. I have a 1972 Chevrolet C20 with the Big Block 402 it is a SCLB. I wanted to know what size rearends came in these trucks I know it probably varies alot but I have no idea at all. Would also like to know what gears and what if any kinda of Posi I can get for it. I am going to try to post pics hope this works!! Also pics are at night so not real good and I have done some things since then also Attached Images Last edited by z7199; 04-06-2005 at 05:13 PM.

04-06-2005, 05:18 PM	#2
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,063	Welcome to the Board from the Netherlands!! Great looking truck you got there, I like the color!! Looks like mine!! Cya, Edmond __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- The Netherlands

04-06-2005, 05:21 PM	#3
Bill72BB Thats the Hillbilly way Join Date: Jul 2001 Location: Torrance,Ca Posts: 5,980	Welcome From So Cal. Do you have Leaf or Coil springs in the rear ? Most Leaf came with a Dana 60 ,3.54 stock many had 4.10 . __________________ BILL Torrance Calif 90504 Member DUF Club Member Old Farts Club 72 3/4ton Custom Camper BB402/400 trans Dynomax Cerama-coat headers , Hei distributor ,Edelbrock 1411 air,ps,pb,leafsprings ,98 chevy 60/40 seat,S10 shoulder belts tilt,3.54 Dana 60 rear. 16" Eagle wheels with LT265/75 16 tires,Gaylord Lid,H4 headlights with 100W relay conversion. " If I knew I was going to live this long I would have taken better care of myself " Marriage changes passion...suddenly you're in bed with a relative. A GUY'S PRAYER.... Lord, I pray for a nympho with huge boobs who owns a liquor store and likes to fish and hunt and has a Harley .Amen ,

04-06-2005, 07:30 PM	#5
Bill72BB Thats the Hillbilly way Join Date: Jul 2001 Location: Torrance,Ca Posts: 5,980	If you don't show an option you probably have 3.54 , the option code for 4.10 was JA1 . __________________ BILL Torrance Calif 90504 Member DUF Club Member Old Farts Club 72 3/4ton Custom Camper BB402/400 trans Dynomax Cerama-coat headers , Hei distributor ,Edelbrock 1411 air,ps,pb,leafsprings ,98 chevy 60/40 seat,S10 shoulder belts tilt,3.54 Dana 60 rear. 16" Eagle wheels with LT265/75 16 tires,Gaylord Lid,H4 headlights with 100W relay conversion. " If I knew I was going to live this long I would have taken better care of myself " Marriage changes passion...suddenly you're in bed with a relative. A GUY'S PRAYER.... Lord, I pray for a nympho with huge boobs who owns a liquor store and likes to fish and hunt and has a Harley .Amen ,

04-06-2005, 08:01 PM	#6
z7199 Registered User Join Date: Apr 2005 Location: Houston TX Posts: 76	Are the current option codes the same as they were in 72? Also what is the best way to make it a Posi/ Limited slip __________________ 99 nbs 5.3L x-cab Hypertech programmer True dual 1 chamber flowmasters magnaflow x-pipe 3" PA body lift 315/75/16 BFG All Terrian 15.3 @ 89mph 72' C20 402ci sc,lb in bed tool box, and new paint http://www.cardomain.com/memberpage/456511/1

04-06-2005, 09:24 PM	#7
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	If it is a dana 60, then the factory limited slip, would be a powr-loc. I t was the max-traction option, can't remember the rpo right now. Nice truck. Welcome to the board! __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

04-06-2005, 10:38 PM	#9
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	option G87 was power- lok. welcome to the boards. As for what gear ratios available...being that you figure the truck was an original BB 402 truck it should have standard equipment 3.54 ratio rear dana 60 rear end. If there are no other listed option on the glove box sticker for options in regard to the rear end gears ratio, then it should have 3.54 if its a true original BB 402. It could have optional gears or 4.10 or even 4.56...but I myself have only seen 4.10 as an option with a BB 402. But any different gear ratio would have been identified on the glove box sticker if it's still readable. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

04-06-2005, 10:43 PM	#10
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	If it's the stock 10 bolt it will be either 4.54 or 4.10 gears. Best way to upgrade is to replace the entire differential with a 14 bolt. They are available in 3.73 and 3.42 in the full floater. Trying to find better gears for a 3/4 ton differential is elusive, at best. The 4.10 gears are getting to be hard to find. Many of us with older 3/4 tons, like my 52, are happy to find the 4.10 gears, the entire pumpkin from the 64-72 swaps right into the older housing. Art Houser was cutting 4.10s at $600 a set, but he was recently lost in a car wreck, so you can't even buy them new. Randy's Ring & Pinion had some 3.90s cut a long time ago, but stopped production. Not many are willing to shell out that much money for a set of gears. __________________ Fred There is no such thing as too much cam...just not enough engine.

04-06-2005, 10:54 PM	#11
z7199 Registered User Join Date: Apr 2005 Location: Houston TX Posts: 76	Well it is the stock 10 bolt and to the best of my knowledge it is a true 3/4 ton with the BB 402 glove box says it is plus has 402 ci on the core support under the hood and emblems. So somebody would have to have done alot of work to make it look like a 3/4 ton BB 402. So Fred you think they got to be 4.10 or 4.56 okay knowing that were can I get a Limited Slip? Or is it still going to be easier to replace with a 14 bolt to get the LSD? __________________ 99 nbs 5.3L x-cab Hypertech programmer True dual 1 chamber flowmasters magnaflow x-pipe 3" PA body lift 315/75/16 BFG All Terrian 15.3 @ 89mph 72' C20 402ci sc,lb in bed tool box, and new paint http://www.cardomain.com/memberpage/456511/1

04-06-2005, 11:19 PM	#12
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Trust me, it's 3.54 gears already if not optioned differently as per the glove box sticker. You might find a power lok on ebay...maybe...but you have to find a 30 spline unit for your dana axles in this era if still a correct dana 60, 67-72 era. If your rear axle looks like this style carrier then it's a dana 60..an older correct 67-72 one as it has ten bolts holding the cover on....count em there's ten bolts holding the cover. If its that shape but has 14 bolts holding the cover then the diffs been swapped already to a 14 bolt rear axle. Attached Images __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

04-06-2005, 11:26 PM	#13
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	I have a dana 60 with 4.10 and the power lok and I have a dana 60 with 3.54 and no posi. Oddly enough there both from coil sprung rear 3/4 ton GMC's. I got some plans for them though, but can take pics if you want in some future time.

04-06-2005, 11:47 PM	#16
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	You probably will hear of one hear one the board before ebay, a power lok posi 30 spline that is..they are are sought after units. Fred T, I sent a 4.10 eaton diff with a detroit locker to a member here on the boards from Texas last month for his 1956 3/4 ton...weighed 142 pounds once crated up. Here's the pic. I heard about Art also... sad. I post a pic of the eaton style diff so you can notice the difference also z7199. The eaton diff come out the front as a unit...easy swap. Being yours is a dana ...not possible to do it like this. The dana gears are 3.54 not 3.56 as you said above. Attached Images __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

04-06-2005, 11:54 PM	#17
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Your basic dana 60 power lok Posi unit looks like this..this pic is of a correct 30 spline dana 60 power-lok which had 4.10's. Thats what you asked to see. Attached Images __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

04-07-2005, 12:19 AM	#18
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	took all of about ten seconds to find one on ebay...but its up to you. dana 60 powerlok 30 spline carrier unit auction link. http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WD1V its not mine and I don't know the seller, buyer beware. Should verify axle size also.

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