s.b.p. disc to b.b.p. disc front conversion 72 demon

I have a cracked a arm and decided to go with some qa1 tubular a arms. While I'm in there I want to upgrade to the big bolt pattern so its the same front and back (dont ask, it came this way when I bought it). I have disc in the front now with what looks like newer calipers and newer lower control arms.

Can I just replace the rotors to the larger bolt pattern or is there more to it?
What would i need to look at/measure to tell?
What miscellaneous parts would I need do the switch?