A swap that I've seen in the past is the aluminum block Olds 215/Rover 3.0 V-8 into the TR-6.

At the time, the limiting factor was finding a GM 4-speed to bolt up to the Olds engine or the difficulty of finding a wrecked Rover.

Yes, it is basically the same engine they put in the TR-7. Using the four-barrel Olds version, you would almost double your horsepower and lighten the front end of the car by about 200 pounds.

So far among diesel options, I like the Quantum.

__________________
1983 300SD "Guderian"
1987 MR2
2015 Camry
2015 Chevy Spark
2006 Hyundai Tucson