... rotors are drilled for the 5x4” bolt pattern
... outside of the hub registers are ... a larger diameter than the SBP drum brake hub registers so original SBP drum rims won’t fit.
... if your current wheels can’t be pushed out close to a 1/2” without hitting the fenders you’d need new wheels
So both Pirate Jack and Dr Diff now custom-make rotors for SBP (I wasn't wrong in saying I had not read that. I'm reading it now). Downside is one will have to go thru them or a machine shop every time you need new rotors, which is a wear item.
But, won't satisfy the OP since he wants to keep his existing SBP wheels and sounds like they won't fit over the machined hubs.
Are there specific "drum rims"? I thought SBP wheels fit all 62-72 cars, whether drum or disk brakes.
Also, his existing tires that he wants to keep may rub against the fenders.
If his existing drum spindles and ball joints are in good condition, adding disk brakes to those would be simplest, but he doesn't want drum spindles, so back to square 1.
