I cant make up my mind. Need your opinion.

[x ReAcT x]

So im at the point where i will be putting a new V8 in the truck and i have reached a dilemma. Either carb or EFI. Kidding of course im going EFI but this is the real predicament: Ls swap or splurge and go for the crate RAMJET 350. One of the main things im hoping for with this swap is Fuel Efficiency. With the LS swap im going to need a variety of things: engine, harness, fuel, motor mounts and transmission adapter. I have a 6000 budget and i really would like to stay in that range. I can get the entire RAMJET 350 with a serpentine system for 6K. Brand New, Never opened, ready to go. So heres some info about the truck. 1986 K1500 with SM465 and 3.42 gears. I would love to swap the transmission and gears but I made the decision to spend money to rebuild the SM465 and put a 600 posi-trac unit in the back. So i cant swap gears or tranny out. So this is where im at.. Which is easier? which is better? LS 6.0L or 5.7L RAMJET 350??