Re: 140ci engine
I had a 1980 140ci 4cyl Mustang Coupe with a manual transmission in my past, but no perfomance mods that I recall, off-hand. I saw recently the 4cyl of the day was rated at 90hp. Supposedly, old time movie actress Bette Davis even drove one.
The Mustang v8's back then weren't all that much better, today's 245ci, 6cyl will smoke um.' I believe the very sweet SVO Turbo Mustangs of the mid 1980's were the same basic 140ci engine, so . . . .
or . . . . just enjoy the better MPG & much lower cost of ownership of normally a asperated powertrain . . . .
Vaya con Dios.