I'm converting the rear axle of my 51 chevy pickup over to an 8.8 while im installing a tci rear leaf spring kit. The kit came with new perches that are for a 3" axle. My 8.8 is 3.25. Am i safe to mark the perches for the new diameter and then open them up a bit so that sit down flush? How precise do i need to be. Is a cardboard disc cut out to mark 3.25 with the calibrated eyeball, then open up with a flap wheel, good enough? Or would i better off having a machinist freind open them up more precisely? Im sure that i'm probably overthinking this! ...just dont want to have problems with my rear end walking down the road sideways.
That's what I did on my 8.8" swap. Just ground them out to fit, and welded them on. I also used the 8.8" donor plates and U bolts.