[Jack21]

I have a Classic Roadsters, not an SPF, but it is a back and forth to work and cruising car. It has power steering, power brakes, heater/defroster, tonneau cover, and soft top. (If I lived in Phoenix, the car would also have A/C in it as well.)

Ford (to me) is a little like IBM. They're overpriced, behind the times, and always seem to shoot themselves in the foot. (Does IBM - I've Been Misled - even make computers anymore?)

If you're a conservative driver (relatively speaking), go with the 351W. But like the man said, sooner or later, you're going to want more power. So you might as well start with the 393 and resist putting your foot in it (disconnect the secondaries) until you learn how to drive it. (It's unlike any other car you've ever driven, and you have a learning curve to contend with.)

The FMS crate motor has the wrong heads (restricted flow), wrong cam (too hot), and wrong intake (too little bottom end - and it might be too tall to fit under the hood) for a street motor. And the warrantee sucks (none).

If you don't mind no warrantee, you might want to consider the short block. Then install the right heads, cam, and intake. If you do mind no warrantee, check with some of the major engine builders listed on this site, or some of your local shops for a motor done right, for less money, with a warrantee.