Just scanned the thread a little bit, but if the only thing keeping you from getting half-fast's motor is cuz it's carbed, I'd say get it and convert in the future (someone correct me if that can't be done with that engine though).

My carbed '87 Xcab 4wd with 30x9.5 tires and 4.10 gears (and 196k miles) can cruise over Donner either way at 60-65 no problem, even 70 in 3rd if I really want to... although I usually don't. Of course, fuel consumption is always a concern, and that will be better with EFI, but since you have to get this done within two weeks, if there's a good deal on a carbed motor, I say go for it.