What size is my rearend? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

into69z · 02-20-2008, 08:43 PM

I am working on my 69 c-20 fleetside, it came stock with a 350/400 turbo and now I have rebuilt the turbo and installed a 454. The rearend gear is too much for freeway runs so I need to know what kind of rearend I have and what would be the best ratio(323,342 etc) would it be easier to swap a late model and if so which one? I think the stock ratio now is 411 but I don't know how to check it....thanks for your help..steve

olblue60@aol.com · 02-20-2008, 08:59 PM

I'm not touching this. LOL!

Arad68 · 02-21-2008, 11:58 AM

Quote:

Originally Posted by olblue60@aol.com

I'm not touching this. LOL!

I will...It is Auntie Matilda size

olblue60@aol.com · 02-20-2008, 09:26 PM

You can easily check the rear by jacking the back up untill the tires are off the ground. Put a chalk line on your driveshaft and rear tire. Slowly turn the tire one rotation and count the number of times that your driveshaft rotates.

into69z · 02-20-2008, 09:44 PM

Thanks....is the rearend a dana 60?

**tll74** · 02-21-2008, 01:32 PM

Quote:

Originally Posted by olblue60@aol.com

You can easily check the rear by jacking the back up untill the tires are off the ground. Put a chalk line on your driveshaft and rear tire. Slowly turn the tire one rotation and count the number of times that your driveshaft rotates.

Helpfull hint...Both tires must turn the same direction at the same time or jack up only one side and turn it twice.

How about putting in a 73-87 14 bolt 10.5 This replaced the drop out in 73. These came in 3.21, 3.42, 3.73, 4.10 and more. 3.21 and 3.42 is rare but was used on 2wd big block trucks. I know of a 3.21 out of a 85 c20. The only problem is the lug nut stud size, they are 9/16" and yours are 1/2". All 71-up c20 or k20 had 9/16". 14 bolt 3.73's is very common and cheap. Is it leaf or coil spring? As I recall most if not all 69 c20's were coil? If coil (compare tube diameter for u-bolts) just change over the trailing arm mounts, if leaf change the spring pads and shock mounts and never worry about it again! oops...Almost forgot, if coil transfer over the track bar mount.

just my $.02 cents.....

No3Fan4Ever · 02-21-2008, 07:50 PM

try finding it here........

http://coloradok5.com/axleguide.shtml

hope this helps

Blue'72 · 02-20-2008, 11:40 PM

My wife's name is Dana, so I guess I've got a.......... Never mind...

Does your rearend have bolts on the outside with a straight side on one side, or is it round with the bolts on the side with the driveline? A dana rear will have a cover that can be removed from the outside and won't be round. Otherwise, a round pumkin would be what's called a corporate rearend.

That's the best of my knowledge anyway. I will be quickly corrected if I'm wrong..

into69z · 02-21-2008, 01:19 AM

my rearend is round in the back with a cover and looks to have 10 bolts-so you are saying that is a corporate rearend?....

Premium72 · 02-21-2008, 02:45 AM

wow thats a personal question to ask a bunch of dudes!.

Blue'72 · 02-21-2008, 02:48 AM

I've got a round butt too!

I can't remember all that I once knew about diffs, and frankly I never really did learn that much, but I believe that's what they call that rearend that you have.

**LockDoc** · 02-21-2008, 03:25 AM

-
This thread might help too....

http://67-72chevytrucks.com/vboard/s...ighlight=ratio

LockDoc

Longhorn Man · 02-21-2008, 03:29 AM

that is the corerate rear, usually refered to as the eaton on here. (corperate axle, eaton diff) The 4.10 is as good as you'll get in there, you'll need another rear end.

retodd7711 · 02-21-2008, 06:03 AM

Quote "What size is my rear end?"

LARGE

Longhorn Man · 02-21-2008, 07:06 AM

blue72 had a good description with one mistake on the eaton ID... the rear cover DOES come off, and the front 3rd member pops out too like a ford 9 inch. Saliad bowl is the normal comparison to the Eaton's diff cover.

crazy longhorn · 02-21-2008, 08:24 AM

Well,your azz is big.....damn sure glad i didnt tell the wifey that(she swings a mean skillet)LOL! What Andy said on the gears ,for the corporate rear

If you can find a BB optioned 3/4 ton, you should find a Dana 60, with 3.54 gears....crazyL

Blue'72 · 02-21-2008, 09:43 AM

Thx LHMan! I wish my memory was.. what were we talking about??

Longhorn Man · 02-21-2008, 10:35 AM

lets go ride bikes!

crazy longhorn · 02-21-2008, 10:43 AM

Quote:

Originally Posted by Longhorn Man

lets go ride bikes!

Kick start or electic start?

Blue'72 · 02-21-2008, 10:47 AM

Quote:

Originally Posted by Longhorn Man

lets go ride bikes!

OMG, I so get that!!

Longhorn Man · 02-21-2008, 11:13 AM

that's actually the punch line to an A.D.D. joke that is way too inapropriate for this board.
Yeah yeah yeah, i know I didn't spell it right, but I don't care.

into69z · 02-21-2008, 10:38 PM

Thanks everyone for your help....I'm still not happy with my rearend. I have access to a 74 1 ton dualley rearend-how much trouble would I have making that rearend a single wheel (ok, 1 wheel one each side!) set up? Thanks

**tll74** · 02-21-2008, 11:25 PM

Well....is this rearend out of a pickup truck or cab & chassis truck? The pickup type will be a Dana 70HD and the c-c will be a 14 bolt. The D70 is way to wide for your truck. Now... the c-c will be a narrower. You could use it and make up the difference with wheel offset. Most all 1 tons had 4.10's or lower. So, I wouldn't go with either one.

into69z · 02-21-2008, 11:43 PM

yeah-its a pick-up dana 70-never thought about the width-the 73-87 regular rearends are the same width as the 69? do you know? thanks

**tll74** · 02-22-2008, 03:32 AM

Wheel flange to wheel flange on the 73-up is 67 inches. What I mean by wheel flange is the flat surface which the wheel fits up against. As for the 72-down trucks I'm not sure. If anything they would be a bit narrower. I have one to measure but the wheels are still on it I could remove them if needed. I have put many of these 73 type in and never noticed a diffence so they must pretty close.

02-20-2008, 08:43 PM	#1
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	What size is my rearend? I am working on my 69 c-20 fleetside, it came stock with a 350/400 turbo and now I have rebuilt the turbo and installed a 454. The rearend gear is too much for freeway runs so I need to know what kind of rearend I have and what would be the best ratio(323,342 etc) would it be easier to swap a late model and if so which one? I think the stock ratio now is 411 but I don't know how to check it....thanks for your help..steve __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

02-20-2008, 08:59 PM	#2
olblue60@aol.com member Join Date: Dec 2003 Location: Silver Spring Md.20901 Posts: 2,031	Re: What size is my rearend? I'm not touching this. LOL! __________________ 1967 C/K10 Chevy Panel 1968 C/K20 Chevy Pickup 1968 C/K10 Chevy Suburban 1941 Chevy Sedan Delivery 1960 Chevy Sedan Delivery 1972 Camaro SS 396 #s matching 1971 Harley FX Superglide

02-20-2008, 09:26 PM	#4
olblue60@aol.com member Join Date: Dec 2003 Location: Silver Spring Md.20901 Posts: 2,031	Re: What size is my rearend? You can easily check the rear by jacking the back up untill the tires are off the ground. Put a chalk line on your driveshaft and rear tire. Slowly turn the tire one rotation and count the number of times that your driveshaft rotates. __________________ 1967 C/K10 Chevy Panel 1968 C/K20 Chevy Pickup 1968 C/K10 Chevy Suburban 1941 Chevy Sedan Delivery 1960 Chevy Sedan Delivery 1972 Camaro SS 396 #s matching 1971 Harley FX Superglide

02-20-2008, 09:44 PM	#5
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	Re: What size is my rearend? Thanks....is the rearend a dana 60? __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

02-21-2008, 07:50 PM	#7
No3Fan4Ever Running on empty Join Date: Aug 2002 Location: Roanoke, Virginia Posts: 1,033	Re: What size is my rearend? try finding it here........ http://coloradok5.com/axleguide.shtml hope this helps __________________ _____________________________________________ Tim We have two rules here at the Rock. Rule #1: No writing on the walls. Rule#2: Obey all rules 70 GMC Sierra Grande "Custom Camper" Longhorn 402 Big Block TH400 PS PB factory AC Posi; 94 Bronco XLT 302, auto;worn out daily driver

02-20-2008, 11:40 PM	#8
Blue'72 Skinned knuckles Join Date: Oct 2006 Location: Longview, Washington Posts: 1,126	Re: What size is my rearend? My wife's name is Dana, so I guess I've got a.......... Never mind... Does your rearend have bolts on the outside with a straight side on one side, or is it round with the bolts on the side with the driveline? A dana rear will have a cover that can be removed from the outside and won't be round. Otherwise, a round pumkin would be what's called a corporate rearend. That's the best of my knowledge anyway. I will be quickly corrected if I'm wrong.. __________________ '72 C-10 longbox soon to be short step! '72 Chevelle (sold in January) '07 Sebring '01 Ranger (I've gotta long commute..) If you try to fail, and succeed, which have you done? My build thread - http://67-72chevytrucks.com/vboard/s...d.php?t=276904

02-21-2008, 01:19 AM	#9
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	Re: What size is my rearend? my rearend is round in the back with a cover and looks to have 10 bolts-so you are saying that is a corporate rearend?.... __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

02-21-2008, 02:45 AM	#10
Premium72 Registered User Join Date: Sep 2005 Location: Villa Rica Ga Posts: 889	Re: What size is my rearend? wow thats a personal question to ask a bunch of dudes!. __________________ WombatFire, Art-Design-MADNESS Follow My Build and Adventures on Instagram

02-21-2008, 02:48 AM	#11
Blue'72 Skinned knuckles Join Date: Oct 2006 Location: Longview, Washington Posts: 1,126	Re: What size is my rearend? I've got a round butt too! I can't remember all that I once knew about diffs, and frankly I never really did learn that much, but I believe that's what they call that rearend that you have. __________________ '72 C-10 longbox soon to be short step! '72 Chevelle (sold in January) '07 Sebring '01 Ranger (I've gotta long commute..) If you try to fail, and succeed, which have you done? My build thread - http://67-72chevytrucks.com/vboard/s...d.php?t=276904 Last edited by Blue'72; 02-21-2008 at 02:51 AM.

02-21-2008, 03:25 AM	#12
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,420	Re: What size is my rearend? - This thread might help too.... http://67-72chevytrucks.com/vboard/s...ighlight=ratio LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

02-21-2008, 03:29 AM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: What size is my rearend? that is the corerate rear, usually refered to as the eaton on here. (corperate axle, eaton diff) The 4.10 is as good as you'll get in there, you'll need another rear end.

02-21-2008, 06:03 AM	#14
retodd7711 chrome makes it go FASTER! Join Date: Feb 2007 Location: Cleveland Tennessee Posts: 2,884	Re: What size is my rearend? Quote "What size is my rear end?" LARGE __________________ She can't cook and she won't clean. But she looks good in a skirt and she brings me beer. She can stay for now. EDIT:: But she left me anyway, So forget her. 1962 GMC Stepside V6 4 speed My rolling resto thread http://67-72chevytrucks.com/vboard/s...d.php?t=324226 My old farm truck http://67-72chevytrucks.com/vboard/s...=1#post3465005

02-21-2008, 07:06 AM	#15
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: What size is my rearend? blue72 had a good description with one mistake on the eaton ID... the rear cover DOES come off, and the front 3rd member pops out too like a ford 9 inch. Saliad bowl is the normal comparison to the Eaton's diff cover.

02-21-2008, 08:24 AM	#16
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: What size is my rearend? Well,your azz is big.....damn sure glad i didnt tell the wifey that(she swings a mean skillet)LOL! What Andy said on the gears ,for the corporate rear If you can find a BB optioned 3/4 ton, you should find a Dana 60, with 3.54 gears....crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

02-21-2008, 09:43 AM	#17
Blue'72 Skinned knuckles Join Date: Oct 2006 Location: Longview, Washington Posts: 1,126	Re: What size is my rearend? Thx LHMan! I wish my memory was.. what were we talking about?? __________________ '72 C-10 longbox soon to be short step! '72 Chevelle (sold in January) '07 Sebring '01 Ranger (I've gotta long commute..) If you try to fail, and succeed, which have you done? My build thread - http://67-72chevytrucks.com/vboard/s...d.php?t=276904



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02-21-2008, 10:35 AM	#18
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: What size is my rearend? lets go ride bikes!

02-21-2008, 11:13 AM	#21
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: What size is my rearend? that's actually the punch line to an A.D.D. joke that is way too inapropriate for this board. Yeah yeah yeah, i know I didn't spell it right, but I don't care.

02-21-2008, 10:38 PM	#22
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	Re: What size is my rearend? Thanks everyone for your help....I'm still not happy with my rearend. I have access to a 74 1 ton dualley rearend-how much trouble would I have making that rearend a single wheel (ok, 1 wheel one each side!) set up? Thanks __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

02-21-2008, 11:25 PM	#23
tll74 "Junkyard Dog" Join Date: Jan 2008 Location: Springfield Oregon Posts: 2,527	Re: What size is my rearend? Well....is this rearend out of a pickup truck or cab & chassis truck? The pickup type will be a Dana 70HD and the c-c will be a 14 bolt. The D70 is way to wide for your truck. Now... the c-c will be a narrower. You could use it and make up the difference with wheel offset. Most all 1 tons had 4.10's or lower. So, I wouldn't go with either one.

02-21-2008, 11:43 PM	#24
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	Re: What size is my rearend? yeah-its a pick-up dana 70-never thought about the width-the 73-87 regular rearends are the same width as the 69? do you know? thanks __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

02-22-2008, 03:32 AM	#25
tll74 "Junkyard Dog" Join Date: Jan 2008 Location: Springfield Oregon Posts: 2,527	Re: What size is my rearend? Wheel flange to wheel flange on the 73-up is 67 inches. What I mean by wheel flange is the flat surface which the wheel fits up against. As for the 72-down trucks I'm not sure. If anything they would be a bit narrower. I have one to measure but the wheels are still on it I could remove them if needed. I have put many of these 73 type in and never noticed a diffence so they must pretty close.

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