I decided to go ahead and box up my new FRPP UCA's while I'm waiting on gears. Just posting a little write up in case it might help someone out.
I used 1/4" plate which is about the same thickness as the control arms. The demesions I came up with for the plates are 1.5" wide on the chassis end, 2.75" wide on the axle end, 4.5" long. I set the plates about 2.5" from the center of the chassis bushing. You could box more or less, depending on what you think. My less is better attitude told me the chassis end is pretty strong so I didn't box the whole thing. The arms are glavanized so grind the surface where you're going to be welding. I put a little bow in the plates as you can see in the picture to match up with the arms a little better.
I used 1/4" plate which is about the same thickness as the control arms. The demesions I came up with for the plates are 1.5" wide on the chassis end, 2.75" wide on the axle end, 4.5" long. I set the plates about 2.5" from the center of the chassis bushing. You could box more or less, depending on what you think. My less is better attitude told me the chassis end is pretty strong so I didn't box the whole thing. The arms are glavanized so grind the surface where you're going to be welding. I put a little bow in the plates as you can see in the picture to match up with the arms a little better.