Have you considered going to an Isuzu commercial dealer and talking to them about radiators from industrial 4JB1T(C) applications? Your nearest Isuzu commercial dealer parts manager could become your new best friend...

I'd recommend going to the parts department first thing in the AM and bringing a dozen donuts every time you go. In six weeks you'll have an entire parts depart that's thrilled every time they see you--even though they know you've got some unusual and difficult to fill request.

I am still anxiously awaiting your report on whether or not the engine actually bolts right in. I still have a potential project rig just waiting for an engine...