Ah yes.. I remember this idea and let me just say I LOVE IT. Five years ago I would have been afraid of such a task for several reasons.
After cutting up and morphing so many different vehicles into one at this point, I know it can be done and it's not difficult at all.
A few things to consider:
1. Don't over think it. Hell, don't think too much about it at all.
2. Those technical drawings? Throw those out, straight to the wheelie bin, be sure to recycle. Or not.
3. Buy both vehicles and a pack of 4.5" cut off grinder wheels and two packs of sawzall blades. Fine teeth, a pack of long & a pack of short.
4. Weight balance considerations? No. That takes drawings and technical computering stuff, best left for manufacturers. We "aint' got that kinda time".
5. Set one goal- Off roading puddle jumper or a road going smooth tire noise maker, imitating a track vehicle.
With the ride height of the suspension on the RAV, you're never going to get the CG balance to change to match the low slung shell of an SW. It makes no sense to move suspension pickup points from one floor pan to another. You'll need lasers, corner scales- I mean, it should take months to be on the road, not years. Even if you over engineered a build like this, made it show quality worthy and did it "right", you'll never get your money back out of it when you sell it, so really- quit thinkin' and Git ta Gittin'.
I've used a lot of vehicles with standard truck frames and this chop & plop- is a little different, but just as simple- So the easy way to do this- is to leave the complete RAV driveline, fueling, suspension pickup points and entire floor pan, electrical system- EVERYTHING as it is. Move the wires out of the way and give it a haircut. a Biiiig haircut. Make it a drivable RAV floorpan with engine and wheels. Once you have that, drive it around and film it because it's funny looking and cool. Be sure to chop off exhaust for vroom vroom sounds.
Then figure out a way to suspend the SW20 shell in the air. This is what I would do- remove the engine and interior, wires. Liberate it from the floor pan, all the way around. Because they flex- weld a couple cheap braces across the interior door openings, maybe one across the back. Nothing too serious, just make sure you don't break the glass is all. A dent here or there or a weld burn, no big deal, they make hammers and paint for that.
Lift the hollowed out shell into the air. Drive the rav floor pan under it. You could push it under, but where's the fun in that? Again, film such nonsense.
Line it up best you can and cut away what hits. Once you lower the SW20 shell down on the RAV floor, you simply patch the floor, making little cardboard templates for each piece. Make it out of cardboard first, then sheet metal, then weld it in.
Once connected, use seam sealer to close up the stitch welds that will be all over the place, paint to match. Next plug all your RAV wires back in, mount the dash in some way and get it to move under it's own power. Then worry about cosmetics, but don't worry too much, most of the joy comes from other people seeing it drive down the road or flying through the air.
And that's it. This should take no more than 150-200 hours of labor to complete. Two good guys could get it done a week if they focused solely on the task.
Refer to step one. Oh- and be sure to drink lots of beer after the grinders and saws are put down for the day.
? Oh FFS somebody fly me over there and get outta the way, I'll do it for free hahaha