small bolt pattern to big bolt pattern

These guys are giving you good advice.
What ever you do, it's a pain in the butt ! Better get the big picture before you make a move.

It's gonna cost ! Don't add it up !

New brakes, new MC, new axles and with which bearing, new tires, new rims, NEW, NEW, NEW, and NEW !
Who's going to install ?
It's only MaMaMoneeey ! But it's worth it !
Just kidding ! It's the Best thing I ever did to my car. After 40 years, it was time to upgrade and I think it paid off.
I had front discs, Kelsey Hayes, had the rotors re-drilled.

Got the Summit rear disc conversion.

Bought the regular moser axles, not race, a lot cheaper and 90% as good, so it's plenty good, with the green bearings and long studs, installed free on them by Moser, through Summit, with free shipping.

Talk to DR. Diff, and see what he has, is my suggestion.
He might have everything you need, except for rims and tires.
He might have a package deal.

After I found out about him, I bought my universals and drive shaft from him.
Take your time! The type of rear axle bearing you use might determine the brake system you use.
When money doesn't come easy, I thought I was never going to get done with the rest of the car, but it's getting there.