Optional rear springs
 

I see mention from time to time, in other places on the net, that in trucks from 67-72, Chevy had coil rear springs and GMC had leaf's.

This may have already been hashed, but on all the GMC SPID's I have looked at, leaf springs are listed as an option, but I have never seen a coil spring listed as an option.

Can someone show me a GMC SPID with a coil spring option?

Re: Optional rear springs
 

Subd. This will be an interesting one.

Re: Optional rear springs
 

Coil springs are not listed as they are standard equipment

Leafs are listed as they are optional

I have 2 69 c20 truck one a gmc the other a chevy both leaf sprung

Re: Optional rear springs
 

What he said ^^^^. My 68 chevy only mentions heavy springs it has coils all 4 corners. My 72
chevy custom camper list the leafs on the SPID as they were optional

Re: Optional rear springs
 

I'm not trying to be a smartass (Well maybe I am.) Leon, but, show me.

I have looked at several GMC SPIDS, and like Chevrolet, leaf springs are listed as an option.

That's the reason I asked to see a SPID listing a coil spring option.

A friend of mine has a coil spring 72 GMC, and there is no mention of springs on the SPID.

Re: Optional rear springs
 

BTW Leon, is there a truck show in KC this year?

Re: Optional rear springs
 

The truck show in Kansas City was canceled a few days ago, Carrie from Classic parts text me to say they unfortunately decided to cancel it

Re: Optional rear springs
 

Simply put, I want to see a GMC SPID with a coil spring option.

Re: Optional rear springs
 

You may be seeing heavy duty leafs as an option .

Re: Optional rear springs
 

Special-k sez in 2016: "You will never see a SPID showing a "Coil Spring" option."

LockDoc

Re: Optional rear springs
 

The truck show in Kansas City was canceled a few days ago, Carrie from Classic parts text me to say they unfortunately decided to cancel it

Re: Optional rear springs
 

Doesn't that prove my point Leon?

The SPID lists options. GMC's with leafs always have it listed on the SPID which means they were optional.

My friends truck started me thinking about this. His GMC has coil springs that are not listed on the SPID. If they were an option they would be listed, which says to me coils were standard.

Re: Optional rear springs
 

Yes coils on a 2 wheel drive where standard chevy and gmc

I double checked my 68 gmc spid list hd springs no list of rear coil
My 69 chevy list hd rear springs and list rear leaf springs

Re: Optional rear springs
 

I'm just going by what the concensus has been on the the board over the years.

Read this thread, you will be more confused than ever.

http://67-72chevytrucks.com/vboard/s...d.php?t=701462

Some say one thing and some say another. Actually to me it doesn't make any difference whether they have coils or leafs since it isn't that hard to change them from one to the other..... I have changed two trucks from leafs to coils over the years and I am in the process of installing a '67 HO72 rear end in a '72 GMC 3/4 ton frame, and changing it from leaf spring to coils.

LockDoc

Re: Optional rear springs
 

Hey Leon, it's all in fun. It makes no difference it the greater scheme of things.

Edit; That info you posted is just what I was looking for.
Thanks, Leon.

Re: Optional rear springs
 

We all know that longhorns came with leafs. What does the SPID on one say? If it lists "G70 R.Susp-leaf springs" then we now know that some models all came with a certain "option". If it just says "G50 Heavy rear spring" and no mention of leafs, that would make more sense. Mine didn't have a SPID so I can't say. -BA

Re: Optional rear springs
 

THanks, All!!!
I'm still learning!!!

Re: Optional rear springs
 

All C/30s and C3500s came with leaf springs. Coil springs were not offered on the 1Ts.

All Longhorns, C/20, C2500, C/30, and C3500 were built on the C/30-C3500 133" SRW Chassis.

Only C/30-C3500s came in 133" WB. That is the 1T shortbed frame with 157" being the longbed.

You will not find Coil Springs listed on any light truck SPID in 67-72. But GMCs came through with Lweaf Springs unless Coil Springs were opted. It just goes to prove you can't rely soley upon the printed word. Why was it done this way? Couldn't tell you and I'm not sure anyone can. Ask them why the 402 is listed as a 396 the second year after they were no longer used. Ask them why Sierra Grande is on many Sierra SPIDS. And ask them why options included in a trim level are listed as if they were an independent option. Hetaers came standard in all trucks. You will not find the heater listed as an option on any trucks. But we know it could be deleted.

For what ever reason the US-built GMCs have the Leaf Springs listed as an option and when they have Coils they are not shown as an options. In reality those trucks are Leaf Spring delete, so no spring option listed.

Now with Canadian built light trucks, C910-C930, it is another matter. Those truly were same as Chevrolet except the GMC grille and markings, such as emblems, tailgate, and horn button... same as post '72 US-builts. What I am saying is Canadian 67-69 910-930s were not offered with the V6 option or any other drivetrain feature only found in GMCs built in the USA. I believe someone will be here showing their Canadian ordering books for GMC stating Coil Springs are standard. Yup, that's because those are actually Chevrolet spec'd GMCs, not the true GMCs such as built in USA

Re: Optional rear springs
 

My '70 Longhorn says "H D REAR SPRING" and is option code G50. Leaf springs, though that is not spelled out, like Mark's G70 reads. I wonder what the difference is? GVW? Mine is 7500 Lbsaccording to the plate on the door jamb.

As a side topic, what does the plate below that one say? The rivets are there but that plate is gone! I never noticed that before. :confused:

Added my SPID.

Re: Optional rear springs
 

My Longhorn SPID.

Re: Optional rear springs
 

G50 is a change in spring rating for both leafs and coil, therefore without G70 the truck should have coil, except in the case of Longhorn where coil is specifically called out as not available.

G70 for 3/4 ton calls out 3-4 specific options: Dana rear axle (and larger drums), Rear HD shocks (RPO G68), 4.56 ratio with certain drive train, 2000lb springs (standard on Longhorn). I do not have anecdotal data, but it seems that Longhorns either could not come with a Dana 60 or any one of the other options included with G70, or it was base equipment and therefore not included.

As for the GMC leaf vs coil debate, I have seen no documentation that supports leafs being standard equipment. In fact, advertising lit (which is not infallible) for 1971 lists both leaf and coil as optional, and neither as standard. My guess until proven otherwise is that coil was standard, but GMC as a brand (possibly catering to fleet/commercial buyers) ordered leaf suspension unless a customer was placing an individual order and specifying otherwise.

Re: Optional rear springs
 

engineering and marketing folks came together for once in their lives just to hatch this evil plot to confuse collectors for years and years - it worked!

here's a couple of longhorn SPIDs for your consideration :)

https://dl.dropbox.com/s/emebwkf2uu767do/SPID.jpg?dl=0

https://dl.dropbox.com/s/m9cwjkhxgi39ww0/SPID.jpg?dl=0

Re: Optional rear springs
 

In Canada you seldom see a leaf spring half ton. When you do it could be a Chev or a GMC. coils were standard. When you get to 3/4 tons I've seen more leafs than coils. I've had a bunch of trucks and parts trucks over the years. Two half tons have had leafs.

Re: Optional rear springs
 

I covered the Canada-built GMCs in my post above. They were Chevrolets with GMC trim/markings. No Canadian 910, 920, or 930 came with the GMC V6.

And the written word on leafs being optional on GMCs is not correct. GMC didn't order trucks, they built them. They all came through (built) with leaf spring unless coil springs were specified (ordered), although what you see in writing contradicts that. This is a case, as in other cases, where you can't go by the "data". Dealer order books state that tow hooks were only available with painted front bumper, and we know from real life experience this simply is not true.

Re: Optional rear springs
 

So, I recently acquired a pile of GMC dealer general letters and service letters and ran across this gem. I understand that the vast majority of surviving GMCs have rear leaf suspension, but this is straight from the horse's mouth. Hopefully it clears up this great debate, at least for 1971!
As for Tow hooks on chrome bumper equipped trucks, I saw a dealer letter that, while referring to series 4500 and up, said that dealers can have the factory install Accessories (i.e., non-RPO equipment) using the Special Equipment process. Light duty trucks were covered under the COPO system, so I would speculate that some keen dealers may have used the COPO system to have the factory install tow hooks, which happen to be both an RPO and an Accessory. Seems to be no different than how Camaros were being outfitted with RPO engines not available as an RPO on that model.