C30 U-bolts vs. C20 U-bolts

[EricS76]

I'm in the process of putting a 14 bolt axle under my C-10. The problem I have is that the C-10 ubolts won't work because the 14 bolt's tube diameter is larger, and the C-30(donor truck) ubolts won't work because they're for 3 inch wide springs, and they bolt on upside down (they are square ubolts, and the threads point down). There are ubolts and spring plates in LMC for C20's. My questions are, are C-20 springs 3in. wide or 2.5in. wide? And, do C-20's use ubolts with the threads up (like a C-10) or square ones, with the threads down (like a C-30)?