2 1/4 to 2 1/2 leaf spring

[davidc22]

Hello, I'm sure there is a post bout this but I was unable to find it. I have a 71 GMC [2WD, LWB] that has 2 1/4 wide leaf springs in the rear. I would like to replace them with 2 1/2 wide springs. My question is what part(s) of the spring to frame mounts/shackles need to be changed, if any? will the 2 1/2 wide springs fit into the mounts used on the 2 1/4 stock springs. If some parts need to be changed any guidance on what/how to acquire them would be appreciated.
Thanks

[LowLifeS10]

Im in the process of converting a 2wd into a 4wd. I had to change the front bracket (in rear) cause the springs didnt fit. I used hangers from a -82 blazer cause that's what I had at home. I was able to use the ones in the back but I had to bend the tabs on the mount a bit.

[72MARIO]

I have looked at this swap a few times. You would need hangers from a 1973-87 1/2 or 3/4 2wd. They should keep the spring pad location bolts in the right place side to side. And you would just have to make sure to measure the position of the axel front to rear to keep drive shaft lenght correct.

[davidc22]

Thanks for the responses. Does anyone know if the 2 1/2" wide springs were used on any of the 67 thru 72 models. I heard the 3/4 ton (C20's) used the 2 1/2" springs and I have even heard they were found on some 1/2 tons.

[72MARIO]

the 1/2 and 3/4 ton 2 wd used 2 1/4 springs thru 1972. All the 4x4 trucks blazers jimmys used 2 1/2 but the spring hangers raise the rear of the truck not sure the exact amount of lift but its inches higher

[Mike C]

The 3/4 ton Longhorn used 2 1/2" springs. I believe the hangers were different than the 4x4 hangers as well.

You can get lowered 2 1/4" springs. I'm curious as to what your reason for swapping is?

[davidc22]

Thanks everyone, I guess it was the 4X4 vs 4X2 [2.5 vs 2.25] that I heard was the primary difference [besides the odd 3/4 ton [probably HD/towing model options]. At the risk of hearing all the eye rolls my long term goal is to convert the truck to a 4X4. the rear springs being the first thing I want to address as I have a failing rear end and while it seems to not be an immediate repair I would like to see if I can gather parts and info to do the 2.5 conversion [rear springs are very tired and are in need of replacement. So unless anybody out there knows of an aftermarket source for hangers/conversion parts I got what I needed [for now]. My more immediate project is to get the heat/AC systems working again [defroster is a must before the cold weather sets in; if I have any issues that I can't find the answer to I will start a new post. Thanks again everyone; This forum is the best!

[Mike C]

4x4 spring hangers are different. So if that is your goal you need a 4x4 donor. They are longer giving added ride height.