A loan? And you've got no time? And you want sideways?
You've got the wrong car. You've REALLY got the wrong car. Sell the Supra for what you can get for it, go find something RWD, cheap and lightweight, and most importantly, running.
For a hard limited $3k, and no time to hunt for parts, even a GTE swap is going to be hard to swing, unless you also happen to have a fully furnished garage with all the tools that you'd ever need at your disposal. Add in no income, so no way to save for things like clutches, TIRES, or even the kind of MAINTENANCE that a Supra needs (Can't skimp on oil changes or coolant flushes) and you'll do something bad to it. Swapping in ANYTHING else for that budget, and you'd better have everything lined up, and either have all the needed parts ready, or the skills to fabricate what you need. (By the way, that -- now sold, I seem to recall -- deal with the 7M-GTE and "everything that you need" deal is probably the only way that you can do this with any kind of time crunch, and engines like that don't come around very often.)
If you're going to swap an engine in that's not a direct replacement for what's in there, you need either money or time. Period.
So... How much time can you afford the car to be off the road, in total?
How much time can you devote to working on it? I took 3 1/2 months, but that was working on it occasional evenings, and most weekends. If you have no income because you have no job, you can probably devote a lot more time to it. If you have little expendable income because you're working to keep your head above water, go back to my statement above. You've got the wrong car.
So let's start over. You'll need to fill in some missing information.
I have: A 19XX Supra, with a 7M-GE engine, {W58/R154/A340E} transmission, XXX,XXX miles, body condition is XXX% that eats head gaskets. Block and head as yet unchecked, assumed to be scrap metal.
I have a $3,000 budget, HARD LIMIT. Can't go over. This has to include all parts, tools, shipping, and payment for services in order to get this project done. (By the way, I still think that using borrowed money for this is NOT smart.)
My car can be down for XX weeks.
My mechanical skills are XXXX. You have {High/Medium/Low} confidence in being able to complete this project without professional assistance.
I have XX hours per week to devote to the project
I have {a few/some/many/most/all} of the tools required to pull a motor, rebuild a motor, and install a motor at my disposal.
I have {no/a} garage available to do the project in.
I want a car that's fun to drive, has more under the pedal than I need for commuter driving, enough to get her sideways, maybe some wheelspin off the line, and {occasional/frequent} drifting.