V1500 with 56" rear leaves...rare?

[jtrux]

I was always under the impression that half ton 4x4's had 52" rear leaves, however, mine has 56" springs.

Is this normal or unusual?

Also, if unusual, is the frame a 3/4 frame or a 1/2 frame with different holes in the rear?

Next dumb question. Are there any appreciable differences between 1/2 and 3/3 frames that have been confirmed? If heard people say that the frames are different thicknesses and what not but has anybody actually measured and verified?

 

[K85 Octane]

V1500? What year is that?
I know my 71 C10 frame was thinner than my 68 C20 lol

 

[jtrux]

1991

 

[Bent77]

1991

56" springs were fairly common, although this site says 64" was the spec for 91. But it's GM, even they don't know what they built...
https://thesuspensionking.com/index.php?route=product/category&path=70_86

 

[jtrux]

Interesting. Thanks.

 

[jtrux]

I did measure my frame this morning and got measurements that ranged from .195 to .210 throughout half a dozen spots.

1991 V1500

 

[kennyw]

My guess is your suburban was ordered with a trailering package that gave you the 56" springs. My wife's 88 V1500 came with 52" springs but the frame has two sets of holes so the rear shackle could be positioned for either length spring.

 

[imiceman44]

56" springs were fairly common, although this site says 64" was the spec for 91. But it's GM, even they don't know what they built...
https://thesuspensionking.com/index.php?route=product/category&path=70_86

Well we're talking suburban here, did you look up 1991 pickup or suburban?
No suburban before 92 got a 64" rear spring

 

[Hogback Fabrication]

'81-91 Suburbans are all over the place, lots of 56's in 1/2 tons and 52's in 3/4 tons (and vice versa). Seems to be about a coin flip as to which length they got in 1/2 and 3/4 ton Suburbans, no idea what dictated which spring was used. The 56's aren't necessarily the heavier spring either.

FWIW, '92-99 Suburbans use ~60" rear springs, shorter than the IFS pickups.

 

[kennyw]

I was always under the impression that half ton 4x4's had 52" rear leaves, however, mine has 56" springs.

Is this normal or unusual?

Also, if unusual, is the frame a 3/4 frame or a 1/2 frame with different holes in the rear?

Next dumb question. Are there any appreciable differences between 1/2 and 3/3 frames that have been confirmed? If heard people say that the frames are different thicknesses and what not but has anybody actually measured and verified?

Does it have a G51 option code? I just picked up an 87 C10/R10 and it has 56" rear springs and a G51 option code "SPRING REAR, HEAVY DUTY, VAR 2"

 

[jtrux]

Nope

 

[K588]

I have a 90 GMC V1500 Suburban that also has rear 56" springs. I'll have to look for that G51 code, always figured it was some option package.

No G51 code on mine.

 

[kennyw]

This is the RPO sheet from the parts truck

 

[USSkoval]

My '88 V1500 Burb had 52's originally, the holes were already in the frame when I put 56's under it. I've had a couple C20 Burbs and a couple other K20 Burbs, they all had 56"s. I'd really like to know why other Burbs had different length springs.

 

[Babaganoosh]

Here is a interesting one, my 82 c10 came with 56's

 

[USSkoval]

Here is a interesting one, my 82 c10 came with 56's

A member on another site has a late 70's shortbed stepside with factory 56's as well. I though that was really odd.

 

[jtrux]

I had a 69 C10 parts truck with 350 (steel crank), TH400 and rear leaves.

Sorta heavy duty for a half ton. Wish I had kept it whole.