Lower Control Arm U-Bolt size
 

I strugged to find this info, so posting it here.

Control Arm U-Bolt Center to Center 2.13"
Control Arm U-Bolt Length 3.44"
Control Arm U-Bolt Thread Size 9/16"-12 UNC-2A

Re: Lower Control Arm U-Bolt size
 

Stock is 1/2" if I remember right ,While you have them apart upgrade to Dorman 13503 which are 9/16 .:chevy:

https://www.summitracing.com/parts/r...SABEgKJvvD_BwE

Re: Lower Control Arm U-Bolt size
 

I used the 9/16" Dorman U-bolts listed above and didn't even have to drill out the holes in the Crossmember for them to fit. Great upgrade for cheap!

Gary

Re: Lower Control Arm U-Bolt size
 

I also used the bigger 9/16 bolts. Also available from gm p/n 345970 (9/16-12x 3 5/32). I am not a big fan of dorman stuff.

Re: Lower Control Arm U-Bolt size
 

I had the 9/16" bolts stock. I know it was original, because it still had the riveted ball joints at 210k miles. :metal: I'll bet that the truck lost 20 pounds of dirt and grease when I rebuilt that front end.