My rear end is definitely an 8 incher, they only came in the 4 speed 22r trucks. I do have a spare complete 7.5 rear end laying around i could swap in that has 3.73 gears. I think ill weld that up to get me burning tires. I would definitely be interested in figuring out how to get a diff from you, if thats on the table. Wether its a 7.5 lsd or an 8, i can use either.Stock mk2 Supra 5spd is a 4.3 rear, with w58, 25.6 inch diameter tires as I recall. Stock mk3 Supra Turbo is 3.9 or 3.73 depending on year, r154 of course, and tires 26inch something diameter.
Are you sure your rear is an 8? My 03 Tacoma has the same 7.5R&P the mk2 does, which is great because I have a couple LSDs laying around. If you do have an 8, you should be able to run the mk3 Supra LSD, which is a really strong unit and not too hard to find. Swapping gear sets is always challenging in diffs btw.
That's awesome you fixed your fuel setup, thats much better and safer for sure.
Oil leaks will appear everywhere if your crankcase is pressurized, I wouldn't worry about the ones you had, just the ones you have. But the leak could easily have come from the valve covers or cam shaft housings where they connect to the head. There is a metal gasket in there that is notorious for leaking after people take them apart, if they havn't cleaned up their surfaces just right or used a new gasket. Most of us add a little spray to those gaskets for extra insurance.
Yeah just take that ISCV out and check out its plunger and what the inside of the hole looks like. Could just be the inside is carboned up so bad the plunger was seized. Thats uncommon, but who knows. Bench test it and you will know if the problem is in the mounting, the valve itself or the wiring.