Chevy vs. GMC Frames - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HeavyK20 · 11-13-2002, 07:59 AM

1. I know chevy coil frames have the bulg in the frame over the rear end.
2. I also know that 4x4's have straight frame rails over the rear end.
3. I also know that the chevy 2wd leaf frames, that I've seen, have the bulg (It looks like leaf springs were retrofit onto coil frame).

The big question is, Do all 2wd leaf frams have the bulg or did GMC or some Chevy years have straight frame rails?

**GMCPaul** · 11-13-2002, 08:25 AM

All of our Chevy 2wd leaf & coil spring truck frames are the same as our 2wd leaf or coil frames. They all bulge.
GMCPaul

Project1970 · 11-13-2002, 02:30 PM

A frame's a frame on these trucks, whether it came from a GMC or a Chevy...only difference is that most Chevy frames were coils, and most GMC frames were leaves. Someone on here had a story as to why that happened, and IIRC it was supposed to be all Chevies were coils and all GMCs were leaves...something about the gov't

crazy longhorn · 11-13-2002, 02:42 PM

The longhorns have the straight rails, but are a totally different frame than the other 2 wd pickups....same as a 133 wb C30

*Fast68Chevy* · 11-13-2002, 02:45 PM

Quote:

Originally posted by Project1970
A frame's a frame on these trucks, whether it came from a GMC or a Chevy...only difference is that most Chevy frames were coils, and most GMC frames were leaves. Someone on here had a story as to why that happened, and IIRC it was supposed to be all Chevies were coils and all GMCs were leaves...something about the gov't

GMC were std equipment G70 leaf type rear and chevy were std equipment coil type rear, this goes for 2wd 1/2 and 3/4 ton only, cept for longhorn like previously mentioned

good luck

johnnyp · 11-13-2002, 03:04 PM

My GMC came with rear coil springs. If they were an option I would have thought it would be listed on the glovebox sticker but it isn't.

yellowgmc · 11-13-2002, 03:05 PM

my 72 gmc has rear coils. how rare are they? there's nothing on my glove box sticker either.

*Fast68Chevy* · 11-13-2002, 03:41 PM

someone needs to get a copy of the GMC specs sheets for these years, anyone here got one, Rod, GMC Paul ??

Project1970 · 11-13-2002, 04:26 PM

I bet they just decided to do the option sheets the same for either, and make even the 'optional' coil-spring GMCs not show a code for it...but standard leaf-spring GMCs do.

Ackattack · 11-13-2002, 05:14 PM

yeah, my truck has the leaf spring "option" on the glove box

HOTFUN · 11-13-2002, 08:58 PM

I looked at my orignal 1972 GMC 1500/2500 sales brochure dated 8/71 and it says for 1500 2wd shows coils standard with leaf springs as optional.
I don't know where this tale of GMC were leaf/ Chevy were coil but I questioned that a long time ago. I too have seen many GMC's with coils. HF

Longhorn Man · 11-14-2002, 12:42 AM

In all honesty, 100% of the GMC's I've dealt with had coils with no mention of it in the glove box.
But that's only 4 trucks though.

cheyenne10 · 11-14-2002, 12:58 AM

So are short leaf and short coil frames the same? Can a short leaf frame be switched to coil buy adding rear trailing arms, coils and rearend? If so are the frame holes there for mounting brackets?

**Richard** · 11-14-2002, 01:46 AM

I have seen the leaf/coil thing posted many times and have no idea where the GMC had leaves standard came from. All the info and literature I have ever seen for both Chev and GMC states that coils are standard on all models except the 4X4, camper specials and longhorns in which coils were not available. My theory is that it has to do with the marketing at the time. The GMC's were considered the working class trucks and the Chev's were marketed as more luxurious. Therefore more GMC's were made and ordered with leafs which are considered more "heavy duty".

lofly'a · 11-14-2002, 05:13 AM

to answer cheyenne10's question, yes they can be swapped. i also asked this ques. of the board about a month ago. have since taked the beds off bith trucks to confirm and plan the knuckle-bustin conversion.

Mike C · 11-14-2002, 09:10 AM

I have had 4 GMC and they have all had leaf springs. It may depend what part of the country you are in. 1 is my Jimmy however, so it is leaves. Also, the 3 two wheel drive trucks I had: 1 was a Longhorn GMC so it had leaves and the other 2 were both 3/4 ton. FWIW, 2 wheel drive trucks have 2 1/4" wide leaf springs while the Longhorns and 4x4 have 2 1/2" wide leafs. At least on 70 and up.

cheyenne10 · 11-14-2002, 01:05 PM

lofly'a;

If you have any pics of both and what it takes to change let me know. Is it just a matter or cutting rivets and moving to the leaf frame?

HeavyK20 · 11-14-2002, 01:08 PM

The question I really had was:

Are all 2wd leaf frames the same as coil frames? iow, Are all 2wd leaf frames 38.5 inches wide above the rear end?

Thanks

Rod · 11-14-2002, 02:13 PM

Well up here in Canada I'd have to say that all GMC's 1/2 and 3/4 ton came with standard coils springs. Any GMC or Chev I have seen with leafs had leafs written as an option on the glove box if the glove box was still there.
Perhaps there was a US plant that made GMC's and used leafs as standard equipment... I really dont know that to be true because Canada had its own GMC plant in Oshawa, Ontario and not as many GMC's from the US states were shipped to Canada. I have owned a 70 3/4 GMC Sierra Grande Camper Special also and it had coils not leafs. So I dont believe all Camper Specials had leafs either.
I have Dealer Data books but there Chevs and I dont own a GMC one... anyone have a GMC data Book. For Sale possibly? Rod

*Fast68Chevy* · 11-14-2002, 03:48 PM

http://www.nidlink.com/~conrad/gmc-history.html

check out whats stated for 1963 info

interesting.,

so anyoen got anyone got a GMC specs sheet book ? or can GMC sheets even be ordered from GM ?

cheyenne10 · 11-14-2002, 08:47 PM

Its a bad habit I have on jumping in on other commnets to clutter posts. Please accept my appology if I did.

I think I also am trying to get same answer are leaf and coil frames the same. Lofly'a helped with thecooment on the ability to switch rear suspensions on 2wd. If frames are the same then it should be just a matter of switching rear suspensions types.

GMCPAul also said frames are all the same. I see buldge your talking about in above post.

11-13-2002, 07:59 AM	#1
HeavyK20 Registered User Join Date: Dec 2001 Location: New Richmond, WI Posts: 547	Chevy vs. GMC Frames 1. I know chevy coil frames have the bulg in the frame over the rear end. 2. I also know that 4x4's have straight frame rails over the rear end. 3. I also know that the chevy 2wd leaf frames, that I've seen, have the bulg (It looks like leaf springs were retrofit onto coil frame). The big question is, Do all 2wd leaf frams have the bulg or did GMC or some Chevy years have straight frame rails? __________________ Eric 1969 K20, 465/205 package

11-13-2002, 08:25 AM	#2
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	All of our Chevy 2wd leaf & coil spring truck frames are the same as our 2wd leaf or coil frames. They all bulge. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

11-13-2002, 02:30 PM	#3
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	A frame's a frame on these trucks, whether it came from a GMC or a Chevy...only difference is that most Chevy frames were coils, and most GMC frames were leaves. Someone on here had a story as to why that happened, and IIRC it was supposed to be all Chevies were coils and all GMCs were leaves...something about the gov't __________________ Project1970 - LS1 Swap Complete!

11-13-2002, 02:42 PM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	The longhorns have the straight rails, but are a totally different frame than the other 2 wd pickups....same as a 133 wb C30 __________________ 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....

11-13-2002, 03:04 PM	#6
johnnyp Keepin' It Stock Join Date: Aug 2001 Location: Grand Island, Nebraska, USA Posts: 554	My GMC came with rear coil springs. If they were an option I would have thought it would be listed on the glovebox sticker but it isn't. Attached Images __________________ 72 Sierra Grande - Maych Forget about "do it right the first time". Do it wrong the first time to learn how, then do it right the second time.

11-13-2002, 03:05 PM	#7
yellowgmc Getting cabin fever?!?!?! Join Date: Oct 2002 Location: chisholm, mn Posts: 1,679	my 72 gmc has rear coils. how rare are they? there's nothing on my glove box sticker either. __________________ Member of the Discs Up Front Club 1972 GMC 1500 1994 F-150 XL 4x4 Tact is for people not whitty enough to be sarcastic

11-13-2002, 03:41 PM	#8
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	someone needs to get a copy of the GMC specs sheets for these years, anyone here got one, Rod, GMC Paul ??

11-13-2002, 04:26 PM	#9
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	I bet they just decided to do the option sheets the same for either, and make even the 'optional' coil-spring GMCs not show a code for it...but standard leaf-spring GMCs do. __________________ Project1970 - LS1 Swap Complete!

11-13-2002, 05:14 PM	#10
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,524	yeah, my truck has the leaf spring "option" on the glove box __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-13-2002, 08:58 PM	#11
HOTFUN Registered User Join Date: Jan 2001 Location: Lincoln, Nebraska Posts: 2,145	I looked at my orignal 1972 GMC 1500/2500 sales brochure dated 8/71 and it says for 1500 2wd shows coils standard with leaf springs as optional. I don't know where this tale of GMC were leaf/ Chevy were coil but I questioned that a long time ago. I too have seen many GMC's with coils. HF __________________ '66 CST BBW swb fleet 327 fac ac '67 CST 4x4 swb 327 stepside project '72 Cheyenne K20 50k original '72 Cheyenne Super K20 project '73 Sierra swb 4x4 frame off in paint stage '74 Cheyenne Super swb w/16k actual '71 & 72 Cheyenne K10 4x4 swb's '70 426 HEMICUDA conv SHAKER 4 sp Dana 60 '60 Impala conv 327 PG fac ac loaded 3rd owner '72 GMC K2500 4x4 '59 Apache CST BBW fleetside swb 283 '73 ElCamino SS LS1 T56 true SS bucket tach '76 ElCamino SS 52k survivor '87 Grand National 41k True 2nd to last built in 1987. '86 K30 454 SRW fleetside CA since new '88 Trans Am GTA 39k bought new 2018 DEMON plum crazy @ 840HP! "Need for speed"

11-14-2002, 12:42 AM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	In all honesty, 100% of the GMC's I've dealt with had coils with no mention of it in the glove box. But that's only 4 trucks though.

11-14-2002, 12:58 AM	#13
cheyenne10 Senior Member Join Date: Apr 2000 Location: Oregon Posts: 2,512	still confused!! So are short leaf and short coil frames the same? Can a short leaf frame be switched to coil buy adding rear trailing arms, coils and rearend? If so are the frame holes there for mounting brackets? __________________ Bob

11-14-2002, 01:46 AM	#14
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,881	I have seen the leaf/coil thing posted many times and have no idea where the GMC had leaves standard came from. All the info and literature I have ever seen for both Chev and GMC states that coils are standard on all models except the 4X4, camper specials and longhorns in which coils were not available. My theory is that it has to do with the marketing at the time. The GMC's were considered the working class trucks and the Chev's were marketed as more luxurious. Therefore more GMC's were made and ordered with leafs which are considered more "heavy duty". __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

11-14-2002, 05:13 AM	#15
lofly'a Registered User Join Date: May 2000 Location: Alexandria, LA 71301 Posts: 1,451	can swap to answer cheyenne10's question, yes they can be swapped. i also asked this ques. of the board about a month ago. have since taked the beds off bith trucks to confirm and plan the knuckle-bustin conversion. __________________ -02 avalanche (daily driver) -66 gto ragtop 389/400 (garage queen, hand-me-down from dad) -72 Tribute Trans Am (6.0LS/T56 6-speed) in progress -2003 YUKON (Wife's) -71 gmc swb fleet (current project, gonna shave everything, bags, stuff w/ 20's, gen III powertrain) -48 3100 SWB - 12/31/23 LONG TERM Project

11-14-2002, 09:10 AM	#16
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	I have had 4 GMC and they have all had leaf springs. It may depend what part of the country you are in. 1 is my Jimmy however, so it is leaves. Also, the 3 two wheel drive trucks I had: 1 was a Longhorn GMC so it had leaves and the other 2 were both 3/4 ton. FWIW, 2 wheel drive trucks have 2 1/4" wide leaf springs while the Longhorns and 4x4 have 2 1/2" wide leafs. At least on 70 and up. __________________ 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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11-14-2002, 01:05 PM	#17
cheyenne10 Senior Member Join Date: Apr 2000 Location: Oregon Posts: 2,512	lofly'a lofly'a; If you have any pics of both and what it takes to change let me know. Is it just a matter or cutting rivets and moving to the leaf frame? __________________ Bob

11-14-2002, 01:08 PM	#18
HeavyK20 Registered User Join Date: Dec 2001 Location: New Richmond, WI Posts: 547	The question I really had was: Are all 2wd leaf frames the same as coil frames? iow, Are all 2wd leaf frames 38.5 inches wide above the rear end? Thanks __________________ Eric 1969 K20, 465/205 package Last edited by HeavyK20; 11-14-2002 at 02:11 PM.

11-14-2002, 02:13 PM	#19
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Well up here in Canada I'd have to say that all GMC's 1/2 and 3/4 ton came with standard coils springs. Any GMC or Chev I have seen with leafs had leafs written as an option on the glove box if the glove box was still there. Perhaps there was a US plant that made GMC's and used leafs as standard equipment... I really dont know that to be true because Canada had its own GMC plant in Oshawa, Ontario and not as many GMC's from the US states were shipped to Canada. I have owned a 70 3/4 GMC Sierra Grande Camper Special also and it had coils not leafs. So I dont believe all Camper Specials had leafs either. I have Dealer Data books but there Chevs and I dont own a GMC one... anyone have a GMC data Book. For Sale possibly? Rod __________________ 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.

11-14-2002, 03:48 PM	#20
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	http://www.nidlink.com/~conrad/gmc-history.html check out whats stated for 1963 info interesting., so anyoen got anyone got a GMC specs sheet book ? or can GMC sheets even be ordered from GM ? Last edited by Fast68Chevy; 11-14-2002 at 03:53 PM.

11-14-2002, 08:47 PM	#21
cheyenne10 Senior Member Join Date: Apr 2000 Location: Oregon Posts: 2,512	sorry if I clutter your post. Its a bad habit I have on jumping in on other commnets to clutter posts. Please accept my appology if I did. I think I also am trying to get same answer are leaf and coil frames the same. Lofly'a helped with thecooment on the ability to switch rear suspensions on 2wd. If frames are the same then it should be just a matter of switching rear suspensions types. GMCPAul also said frames are all the same. I see buldge your talking about in above post. __________________ Bob

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