Alright, so it seems we're about 1:1 on gas vs diesel... I'm curious if the 350 with TBI would be able to get 20mpg, I looked around elsewhere and all they seem to think is that it can't get any higher than around 16mpg... (
Then again, I would bet you those guys on other forums have lead feet and non-mpg friendly driving techniques... ) I don't think a complete drivetrain swap would have the best of investment return times, so thats why I'm not too fond of that idea. I'll get some fuel prices soon for comparisons sake.
Edit: unfortunately I am from salt country, but I have seen a few fairly clean trucks on craigslist.