Thanks Jerry!
I'll keep you in mind when I need that new head assy.

When the valve let go, I was just warming up my truck. It's a good thing I heard something give and shut it off quick. If I was on the road or at the strip, for sure the damage would of been worse.
I was able to press out an old guide from a spare cracked head. It fit ok, with a little play. So I used a punch to re-shape the ends of the guide bore. I also used some lock-tight to help secure the guide in place.
Got everything back together last night and ran the motor about 5-miles. I wish the Isuzu dealership here carried parts. I would of spent the extra cash for genuine valves for sure!

I think the valve let go becasue of the spring/retainer combo I was using. When I first re-built the motor, I used Toyota 22r springs/retainers. The #2 Toyota spring that snapped was due to slight spring bind. I'm hoping the valve that snapped had to do with the spring bind too.

I replaced all the springs/retainers with the combo I had on my 2.3 motor, Dual springs this time!

Hope to make a few passes without ruining my bottom end...