Hmmm? Seems like differant sites have differant specs for that cam, probably same grind has higher low end RPM range in 4.3 then one I looked at was 5.7 on eBay... did you degree that cam when installed?

Sure could be timing related! We will know when you go without that crane box, but then you've checked timing? I'd like to see that swinging WB AFR go away... I'm kinda lost. We did have a thread here about a 5.7L vortec head swap and found a export 5.7L TBI bin and timing tables were completly differant. Have you compared them to what you have? It looks like a 9.8 degree bias on top of your off throttle timing table IIRC...

Since your doing some testing tomorrow you could add some timing in that range and see if it starts to put out some power? Or if you had a set of smaller tires like 33s would get some more RPM and see if it comes to life?