Sorry, I misunderstood. I used one of those Dimension 260mm forks on a 197mm head tube, it's tight. 40mm is a typical stem's stack, it's easy to find a 30mm stack HS, that should just fit your bike's 190mm headtube, you might need a 5mm spacer.

here's a Cane Creek S1 headset with 27.4mm stack, $30:
http://www.universalcycles.com/shopp...8&category=101