'71 Demon suspension

Getting ready to restore my 71 Demon. Pulled the K frame and suspension out. Car is originally drums all the way around. I want to put discs up front. What is easiest way to do this? Looked at the Willwood setup and that changes my bolt pattern. Not 100% against changing to 4.5" bolt pattern but part of me wants to keep the 4".

What are my options off the factory K frame? With the Willwood setup what else do I need to change? Prop valve, master cylinder, upper control arms?

Part of me wants a nice bolt in replacement setup if possible.

Any opinions are appreciated.

Thanks !