I found a set of marine 4bt's about 3 hours away from me for $1500 each. I have a 2000 f150 with an m5od-r2 tranny in it, so it makes a perfect swap host. I was no intending on starting the swap for a while, but I like to look for motors on craigslist. I know the ancillary components are completely different on the marine engines, but for this price couldn't I swap them out for truck parts later on? I know some sets of twin marine motors rotate in opposite directions, and they could be tuned differently. Just curious if I should even spend my time considering it. I have tried researching it, but I'm coming up empty handed. Maybe for good reason...? I haven't talked to the guy selling them yet, I want to find out more about these types of motors before I waste mine and the sellers time going to look at them. Would I be better off buying a used motor from a reputable online dealer, when I get serious about starting the swap later on? Or should I be shopping around to try and find a local used one when the opportunity arises?