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#26 |
6>8 Plugless........
![]() Join Date: Sep 2007
Location: Prairie City, Ia
Posts: 17,140
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Re: Optional rear springs
I've never personally seen a 2wd GMC with coil springs. I've heard they existed but it's rare enough to see a GMC around here anyway.
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Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project Tired of spark plugs? Check this out. |
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#27 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,721
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Re: Optional rear springs
I currently have a ‘71 GMC 1500 127” wheelbase v-eight truck that is a factory big block and coil spring truck. My buddy has a ‘71 GMC as well with factory coils and is a small block truck.
2500 series GMC trucks from 69-70 is where most of my experience lies and I have had 4 of those. A ‘69 127” 350 small block truck that is leafs and a 7000# gvwr, a ‘70 127” wb 6 cylinder 3 speed truck with leafs and a 6600# gvwr, a ‘70 Longhorn small block 4 speed truck with 6600# gvwr which is obviously leafs, and a ‘70 big block turbo 400 truck that had a 7500# gvwr with the HD leafs. One of the things I find interesting is just how much variance there was within the 2500 platform for GVWR. The “3/4 ton trucks” capacity could vary by more than half a ton! Special K is correct in his analysis, in my opinion, that GMC spec’d leafs on trucks unless coils were specific ordered. And since the trucks were made on the same assembly lines, they used the same nomenclature for the Chevy and GMC trucks for consistency which explained the paper trail. And you are correct in stating, “At least for 1971” with your paperwork!
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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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#28 |
Senior Member
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Location: Harrison, Arkansas
Posts: 9,815
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Re: Optional rear springs
I personally have never seen a half ton GMC with a standard coil spring option on the SPID.
This 72 GMC belongs to my friend. It has coils in the rear, and no mention at all of springs in the SPID.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#29 | |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,440
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Re: Optional rear springs
Quote:
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#30 | |
Active Member
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Location: Central Coast, CA
Posts: 126
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Re: Optional rear springs
Quote:
C1500 Series Standard rear springs are coil rated at 1250. C2500 Series (includes 2590 and 2600 models) The 2590 model has coil rear springs rated at 2000lbs. each as standard The 2600 model has leaf rear springs rated at 2750 lbs. each. This is also why on Longhorns, you don't see G70 for HD leafs. It is standard equipment. As for the torque thing, I agree its a crazy big number but I can't speak to whether or not that's a typo or just how medium duty rear ends are.
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1971 Pontiac Firebird 1971 GMC C2500 |
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#31 |
Registered User
Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,786
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Re: Optional rear springs
I've been using these 600lb wrenches in every shop I've worked in the last 30 years.. add torque multipliers for big jobs..
![]() my guys are lazy nowadays, this hytorc gun runs 25 - 700 ft-lbs one handed ![]() ![]() ![]()
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I started out with nothing - and I still have most of it |
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#32 |
All about them K’s
![]() Join Date: Jun 2014
Location: Land of Entrapment
Posts: 6,392
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Re: Optional rear springs
Yep we use 650 ftlb 3/4 drive Proto torque wrenches and multipliers on our big Ajax compressors, and some of the bigger Waukesha’s at work. Takes a big ole boy to run the 3/4’s. At 5-9 and 170lbs I don’t have enough lead in my ass to do it most days.
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's |
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#33 | |
Registered User
Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,786
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Re: Optional rear springs
Quote:
![]() I've got plenty of ballast but thankfully I don't have to yank on those anymore.. pinions, u-bolts, torque arms, load body mounts, cylinders, outriggers, aerial turrets, torque hubs, final drives, mains, head bolts, etc. all workouts I don't miss, especially the ones over head.. for the most part I just need these in my garage nowadays 1/4" dr - 1/2" dr ![]() ![]()
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I started out with nothing - and I still have most of it |
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#34 | |
Active Member
![]() Join Date: Jun 2018
Location: Central Coast, CA
Posts: 126
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Re: Optional rear springs
Quote:
Yeah. So in '71 the GVWR goes from 6200-7500, but what's really funny is that the front/rear "Maximum Weight" can increase depending on the tire type ordered, but unless you got the bigger springs the GVWR won't, and vice versa. So there are trucks out there with the heavy spring option(s) but because they have base tires, they get the lowest GVWR rating. Seems like dealerships didn't really understand how it all worked, or didn't care. My truck happened to come with the base springs but heavier tires. ![]()
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1971 Pontiac Firebird 1971 GMC C2500 |
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#35 |
Active Member
![]() Join Date: Jun 2018
Location: Central Coast, CA
Posts: 126
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Re: Optional rear springs
Found the "reference" letter from February, 1971. Look at the Note:
"These models have coil rear springs as the standard rear suspension. If a customer does not want coil springs, he can order RPO-G70, which is a two-stage rear leaf spring with the same rated capacity as the standard coil spring." I see no logical reason why by year 4 of the model run, GMC would be spreading erroneous information to their dealers on multiple occasions. Coils must have been standard, but dealers felt like populating their lots with G70 equipped trucks.
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1971 Pontiac Firebird 1971 GMC C2500 |
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#36 |
Senior Member
![]() Join Date: Dec 1999
Location: Southern California
Posts: 2,810
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Re: Optional rear springs
My dear old dad long departed from us. Had told me GMC trucks were marketed as work trucks, heavy duty. Where as Chevrolet's were more marketed as a common every day truck. Dealers ordering GMC's to sell with higher rated load capacities does not seem like a bad idea.
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Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746 |
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#37 |
6>8 Plugless........
![]() Join Date: Sep 2007
Location: Prairie City, Ia
Posts: 17,140
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Re: Optional rear springs
Larry, can you share pics of this truck in another thread? IDK if I've seen another Highlander GMC, and a GMC that had the wheel base on the spid. For what ever reason they always have a blank in the WB spot. Maybe this is plant specific as well? I have noticed ST.Louis built GMC's had a WB listed but none of the other ones do.
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Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project Tired of spark plugs? Check this out. Last edited by Dieselwrencher; 03-01-2022 at 06:39 AM. |
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#38 | |
6>8 Plugless........
![]() Join Date: Sep 2007
Location: Prairie City, Ia
Posts: 17,140
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Re: Optional rear springs
Quote:
And, yes, that's just how big medium duty and heavy duty stuff is. Re torquing u bolts sucks. These new electric impacts are mint. ![]()
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Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project Tired of spark plugs? Check this out. |
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#39 | |
6>8 Plugless........
![]() Join Date: Sep 2007
Location: Prairie City, Ia
Posts: 17,140
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Re: Optional rear springs
Quote:
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Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project Tired of spark plugs? Check this out. |
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#40 | |
Active Member
![]() Join Date: Jun 2018
Location: Central Coast, CA
Posts: 126
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Re: Optional rear springs
Quote:
The truth is that between the 3 truck models (15/25/35) and the two sub-models (127"/133"), it is complicated, which is why GMC sent out the Service Letter in April-May, 1971 in post 25 , to "further clarify Data Book specifications concerning the optional rear suspensions available", and help dealers select the appropriate suspension package (post 35)
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1971 Pontiac Firebird 1971 GMC C2500 |
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