[MKS427]

FYI:
Stage II Street to Mild Race
Stage III Wild Street to Full Race
I would consult with them before changing to Stage III to save time. When I asked about taking my Windsor based Dart to 468", Tony said it would drastically shorten the life of the engine and to stick with 427" for long term reliability.
I've only dealt with them once, but if you decide to stick with them, my belief is they will do what is right for you.