How do I switch an 8.25 Small Bolt to a Big Bolt pattern?

Been down this road with a customers 71 duster that came in with sbp axles that were converted to bbp. The drums used were bbp that don't work with sbp alxes. I machined new sbp drums on my mill for bbp and the 10 x 1 3/4 brakes and everything was good. We have since changed the car to moser bbp axles and 10 x 2 1/2 bbp drums for better stopping power. I sold the drums some time ago but still have the axles if you are interested but my advise would be to get bbp axles and drums from the start along with the bigger brakes. The cost of machine work and labor to change over will not save you much. Do it right and be done with it.