Just stop at pats driveline and grab some, or go to napa and have them pull some. There are only a few sizes.
Lock washer, locktie, and stoffer nuts.
U-bolts arent really stronger but they are better for a 4x4 as long as they stay tight. Which they usually dont unless you lock them up really good.
U-bolts are old tech, and straps are new tech for a reason.
The real reason we like them in theis industry is a broken bolt on a strap type leaves you stranded with no way to extract the busted bolt in the bush.
A broken u-bolt is a very easy trail repair.
Just ask for YJ u-bolts. They will work. Or CJ. Its all 1310 stuff at the case. And at the d30 for that matter. Just dont use the rear, a lot of YJ's came with a 1330 joint on the rear axle. Everytihng else is 1310.
Oh, last tip on u-bolts. Dont over tighten. It will deform the cap and cause the joint to fail prematurely. Difficulty keeping them tight, and people over tightening are the two of the main reasons industry moved to straps.