I'm in the Lincoln, Nebraska area and I have several in good shape.
I even get up to Tabor every now and again, due for a visit with Steve anytime soon.
I'm sorry I couldn't help you, as I looked at 4 CR 5.9s and not a damned one would remain standard, however, I have 4 or 5 6.7s that would easily run standard bore.
Thanks mark. Yes I understand the rare need. But don't really wanna bump this motor up...and did look at doing a 5.9/6.7 hybrid motor buuut bit more moola than I expected