I did similar but I also recall that I had to trim a bit for the e-brake spanner to clear the now old seal retainer nut now relocated on the modern backing plate. There was a number of steps getting the upgrade in place and you will need the tools time and space to work these issues. It is not just a bolt on as trimming axle mount flange at the top is needed, changing the backing plate bolt patter on two of the 5 bolts, removing and reusing the original seal retainer. And many do not know the very other step of machining off the step that is a bit wider for the drum to centric align to the original hub. This can be lead to one or two fixes for the modern drum to fit, either a plate to space out the drum across the full face of the hub or the trimming of the backing plate. I had two style drums, finned and not finned, the finned sat about .030 deeper at the rear of the drum and would drag on the backing plate just a tad. The inner clearance was sufficient with both drums and not internal drag issues. I removed about 1/8 inch of the backing plate lip as it had plenty of sacrifical metal to yield to the mod and would not have to mess with aligning an intermediate positioned disc between the hub and the drum.