To replace torsion bars, or no?

[SkyHighColorado]

supposed to be a letter stamped on the end or something, but mine don't have any letters that I could find.

 

[Kyle97GMC]

I could never figure that part out but the ones I put on were 3/4 of inch thicker than the ones I took off so I figured they were definitely rated higher haha

 

[gordinho80]

RPO codes from the donor truck are not possible. I have my RPO codes... FK2 & FK3 I believe are my RPOs for my torsion bars.

 

[Kyle97GMC]

Like I said you'll know if they're bigger right away. Mine were not even close

 

[454cid]

RPO codes from the donor truck are not possible. I have my RPO codes... FK2 & FK3 I believe are my RPOs for my torsion bars.

I beleive those are the keys, not the bars themselves.

Here's a list that I found with Google.
http://www.letsplow.com/showthread.php?t=2223&p=34759#post34759