I know where you are at, and have pondered all the options for an 88 I bought with a bad motor several years ago and after consideration I decided the easiest was to just drop a rebuilt 3.0 back in there. All in all as long as you don't overheat the motor the 3.0 is not a bad motor. It has it's quirks, and wasn't really the power house that folks want it to be, but if taken care of it is a good little reliable motor that will carry a 1st gens weight around fine. With that in mind....
I have a completely rebuilt 3.0, new pistons, rings and bearings, OS valves in the heads. Not overbored or cut, all stock sizes. I had planned to put it in my 88 4Runner that threw a rod, but I don't have the time or space to get into that project right now and I have decided I would just as well sell it and put the $$ towards something else right now.
It needs a timing set to be complete (which I would do if we worked something out) and the lower intake is off so you could make sure you have the right knock sensor to make your connection before putting the manifold back on. (They changed somewhere around the body style change so you would need to make sure the connection would be correct for your harness.)
I also have a set of Downey headers that I would throw in if you are interested. The crank was beautiful, even with over 200k miles on it, just needed a light polish before it went back together. I have a ton of other parts that I will throw in, injectors, intakes, etc. if you want them.
I would have to have more than $300 for it, but I have a pile of parts that will go with it if you are interested. Heck I even had a R150 5speed and the accompanying computer. All you would need is a Marlin or TG adapter to bolt a gear drive case up to it.
I am in Nashville, PM me if you are interested.