In prepping for our the rebuild of our '81, I'm trying to figure out the specs that a new frame should be.
So, I'd like to know what the dimensions are on a newer style 13' frame. I believe it's 3" C-Channel, but trying to figure out exactly which size. From what I can tell, there's 3 thicknesses available of 3" channel iron.
Can anyone tell me more precisely which one is used?