That's more if what you rather want. Supra's are no joke. If they're both stock. The 5.0 will be easier and cheaper to fix up. A good tranny and clutch, headers back dual exhaust, aftermarket heads, will be around 3 to 4000$ plus labor.
If the supra is turbo charged from the factory, it might not have an intercooler. You need a good one. That can drop the temp down 250 degrees. You can do same upgrades I mentioned on the mustang, but there are the turbo upgrades for the supra. A bigger turbo, intercooler, all accessories is a bunch of stuff and will result in good power increase and quicker acceleration.. Could end up being 10k$ in upgrades.
The mustangs cheaper but spending $10,000 in upgrades on a turbo charged motor will get up and go.
But if you spent 10k on a mustang, that'll get up and go too. Its why I'm saying your preference.
It depends. 1st on the condition of the vehicles and secondly on what you want. Better because its faster or faster making it better? Not sure what your looking for. I can tell you that I had an 88 mustang with the 302CID engine (5.0) and it was indeed a hot car but not nice after I was done with it. On the other hand the supra could be in better condition and not so ragged on because of the class of people who drove it when new.Remember that The Toyota aftermarket parts supply was somewhat limited. Not now for sure. Turbos can make the Supra's smoke any stock V8 and some built ones as well. This certainly did not apply to the 302CID mustangs at the time. I bought mine new and ragged on it the whole way. The Supra was fast as well but didn't attract the drag and street racing mentality or people that the 5.0 mustangs did. I am a motor head for sure and love the V-8 engine. I have three vehicles with small block Chevy's A boat, a truck and a G.T.O. (well not sbc) but its all that's left of Chevy). Looking at a FORD once again but not for a couple of years. Good luck.
Stock, a 5.0 mustang was quick for its time, but nothing too impressive. They will run mid-14s at 95-96mph with a good driver. The MKIV Supra Turbo was definitely faster stock, capable of running a [email protected] Both can be easily upgraded to go quicker, but dollar for dollar it's hard to beat the mustang. I personally know someone who built a fox body mustang (it was a 1984) for $1800 that ran 11.70s in 1/4 mile. Including the price of the car. And paint. You can't even get a decent running MKIV Supra for less than $15,000. For that price, you could pick just about any mustang made before 2005 and beat the Supra for less money.
Also, in the Supra world, there's an old, and mostly true addage. "What does a 300hp, 500hp, and 700hp Supra have in common? A. They all run 13s in 1/4 mile." The truth behind it is, while Supras are easy to get big power out of, just with big turbochargers, they don't tend to be able to do much with that power unless the car is already going 75mph. A stock supra will hook up ok on a drag strip, with a little wheelspin on a decent launch to get a 13 out of it. Modify it to get 500hp, and you get a lot more wheelspin, which negates most of the ET advantage. So instead of the stock cars [email protected] 2.1 60', it would now run [email protected] 2.40-2.50 60'. And the 700hp car? Well, the turbo for that car would be so big, that if you use anti-lag, you would just get massive wheelspin, and if you don't, you have massive lag. So it would be dog slow off the line, THEN blow the tires off, then catch traction and make up the time on the big end. This car would run a [email protected] with a 3.8 60'. These aren't necessarily real numbers, but it illustrates the concept.