I showed pictures of the truck to a buddy that is into cars out here, and he convinced me that what I needed to do was swap a K24 Honda into it with a 6 speed transmission from a 350Z behind it. What could possibly go wrong. Apparently the K24 Honda is swapped into all sorts of vehicles as it is capable of handling gobs of power on the stock internals.

Here is the only pic I have with the Nissan engine still installed. It was a pretty tight fit, but it has been done by others, and I am sure I could have made it work.

Here is a torn down K24 Honda in the engine compartment to check for clearance issues. First issue that popped up was the steering link between the steering box and idler arm was in the way of the oil pan, and there was no way I could modify the pan there as the oil pump was in the way. I ended up taking out the link and am in the process of making one that can mount to the bottom of the box arm and idler arm using 5/8" heim joints and 5/8" rod. The only other clearance issue seems to be the water pump and alternator which sit off to the drivers side of the K24 when mounted in a rear drive vehicle. I think I have it figured out well enough that I am going to get a complete JDM engine and start in on the mods needed to clear the steering box.

Looks like there will be plenty of room for a good size radiator and single electric fan.

There even appears to be room for a turbo since the battery is being relocated outside the engine compartment.

Frame and transmission hump are going to need generous massaging to get this beast in there, but at $2000 for a brand new 6 speed, I could not pass up using the latest edition of the 350 Z transmission.
That is all for now until the JDM K24 is sourced and I get an adapter to mate the pieces together.