Hey, I thought everybody picked up thier toys and went home.
It wouldn't take much to bump a 4b to 200 hp.
I would say a small injector upgrade and a timing adjustment
should get you there. Maybe a turbo.
Our R&D guy can rattle off the numbers if you are interested.
We are a cummins dealer/ repair/ performance shop I think we
have about 20 4b's in stock, what are you looking to get for the 6b?