These are the measurements for the holes, front edge of body tub to the rear. Both sides were within an 1/8".
I should have pulled measurements from the bottom lip of the tub to the center of the holes. Someone else will have to pick up my slack.
On the front fender holes, this is what I did:
The pen line on the right marks an obstruction/piece of metal on the back side of the fender. I centered the hole between this obstruction and the end of the fender on the left side. I used a piece of steel as a straight edge, off the existing body holes, to mark the vertical center line of the hole. More on this in a bit.
I drilled the fender holes to the same size as the body holes, I think 23/64". That is pretty good "slack" for a 1/4" stud to pass through.
But, my fender holes are a bit too high. I could not get the fender T bolts to pass through. The holes were a bit high.
So, I opened the fender holes up to 1/2".
With 1/2" holes in the fenders, the rockers slid right in. Still not sure why these holes would not work out when they were the same size and centered off the body holes. I did not want to lower the fenders since they line up with the body tub/grill pretty well. The fenders are actually a hair low, but when lining all this stuff up, it is hard to get every thing 100% perfect everywhere, so you do the best you can. I am happy with how the replacement fenders line up, overall.
Just something to watch out for. Would be interesting to see how the OEM fender holes line up with body tub holes? I plan on eventually pulling the rockers off my green Scrambler so I can paint them black, I guess I will find out then!!
Replacement T bolts. I ended up using stainless washers to prevent the flange nuts from digging into the paint.
The T bolt on the right is for the fender hole. The one on the left is for the body tub. The fender lower protrusion sticks out past the body tub side, hence the shorter T bolts at the fenders.
Before I painted the rocker trim, I cleaned these back side channels thoroughly, and masked them off to prevent gumming them up with paint. You want to be able to slide the T bolts back and forth fairly easily when you go to bolt on the rocker trim.
The T bolt locations on these rocker pieces did not align with the body holes on this tub. IIRC, these rockers came off the original '84 tub. So, I assume these body tub hole locations vary year to year. Who knows? No big deal, with the back channels cleaned and free, it is easy to slide the T bolts into the correct positions.