The most usual engine I saw in a 60's Mustang was a 2.3L intercooled turbo-charged Ford SVO engine in a '66 Mustang coupe. The installation was done by a professional mechanic whose specialty was Ford products. The guy made it look like a factory job. He also claimed the car had more power than the straight 6 the car originally had, which I had no doubt it did. The 200 C.I.D. 6 was only rated for about 120 HP gross and the SVO four banger was rated at 200+ HP net.
The 617 diesel engine would be too heavy for a Mustang anyway.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012