Front drum brakes get large bolt pattern b/e body parts

I swapped the knuckle/spindle, backing plates, Lower ball joints...basically everything between the B body upper control arm and the lower control arm. The B body lower ball joint fits the A body when doing the traditional 11" disc conversion and also when doing this drum swap.
I did this merely to be able to use the 4.5" bolt circle and a set of wheels that I liked for a video movie stunt car. I don't think there is that much gain in going from 9 inch drums to 10 inch drums.