"Motor is the original 390 big block with a fresh rebuild of only 3,000 miles on it and has been rebuilt as the GT motor which was under rated at 335 horse power."
It was an assumption of mine- he stated that it started as a 390, but we don't know if it's a 2V or 4V; then he says that he rebuilt it as the GT motor- I assumed (which has gotten me in trouble in the past) that with his choice of words, it didn't start as the 390-4V that was in the GT. That would leave the X-Code 390-2V, right?
Nothing but an assumption, I'm afraid.
~robotix