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#1 |
Registered User
Join Date: Jan 2009
Location: Oakwood, Ontario, Canada
Posts: 28
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'72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
Have owned this for about 10 yrs and just getting it on the road. Came with no rear bumper and appeared to have had a heavy duty hitch welded to the frame that was removed, had a brake switch mounted under the steering column.
Seems engine revs quite high at cruising speed of 60 mph, just sucks up gas like crazy. How can I determine what rear end ratio is in it ? Whats available in ratios. ? How big of a job is it to change to a different ratio, ? I had someone do the brakes a little while ago and I believe they had to pull the rear axles out, rears are drums, front disc No doubt will have further questions Last edited by oldasi; 09-19-2017 at 04:30 PM. Reason: better title discription |
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#2 |
The Niner
![]() Join Date: Nov 2010
Location: Broad Brook, CT
Posts: 2,494
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
If your rear end cover looks like this then you have an Eaton rear. Ratios are 4.10s and 4.56s. I think they make custom gear sets for them but not positive.
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"A good racer is one whose head is in communication with his balls." - Richie Evans 1970 C/20 - 402/TH400/3.54s - 74K miles 2003 GMC Sierra 2500 - Wheatland Yellow Niner Progression Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=697183 Classic Trucks article: https://www.motortrend.com/features/...et-c20-driven/ |
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#3 |
Six in a row makes it go...
![]() Join Date: Mar 2009
Location: Vacationland: Maine
Posts: 1,346
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
I've heard stories about a short run of 3.90 gears for these years ago, but they are like unicorns and I've never seen any in the wild. It seems like there's enough demand that somebody could make money off another run (are you listening Yukon Gear?).
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67 C20 long step resto: http://67-72chevytrucks.com/vboard/s...d.php?t=342086 66 C10 long step build: http://67-72chevytrucks.com/vboard/s...=1#post3814790 CT to Alaska in a 67 C10: http://67-72chevytrucks.com/vboard/s...d.php?t=399224 “The height of sophistication is simplicity." - Clare Boothe Luce |
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#4 |
Registered User
Join Date: Dec 2009
Location: bisbee, arizona
Posts: 1,529
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
usually its one of only two rear end types.
if you have leaf spring rear suspension its probably a dana 60 rear. if it has a coil spring rear suspension its probably an HO 57 rear the ratio most likely is 4.56 which explains the hi fuel consumption and hi reving. if its a dana rear you may be able to get a different set of gears that are more fuel and hiway friendly if its the HO rear your stuck with those characteristics. it is correct that they come with a 4.10 or 4.56 ratio and several years ago a custom 3.90 ratio was made available thru the aftermarket. but for the expense it would not have changed much search this forum to see what each rear looks like to more certainly identify it. I dont know if a coil dana rear was available but if so its worth the search and you then can install a wide veriety of hiway friendly gears |
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#5 |
Senior Member
![]() ![]() Join Date: Jan 2015
Location: Kearneysville Wv
Posts: 3,940
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
Eaton Ho 52
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#6 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,720
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
All the Longhorn trucks were leaf spring. The '70 I have has a Dana 60 in it. It was a GMC small block 4 speed FWIW.
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44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
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#7 |
Registered User
Join Date: Apr 2011
Location: Klein Texas
Posts: 3,852
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
Since you have an automatic transmission it would likely be beneficial to look into a more modern overdrive transmission. A 700R4/4L60 would work well as would a built up 200-4R
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My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe |
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#8 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,119
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Re: '72 Chev long horn,3/4 ton,350/auto NEED REAR END INFO
Here are the Power Train Specs for the 72 model. Unless there is an optional rear end ratio listed on the spid compare this chart to your trucks power train.
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