What are 351 F4TE and intake & heads worth ?

Not a whole lot. It should have E7TE heads which came on all '87-95 5.0L Mustangs. If they are in really good shape, maybe 150. Intake probably 75 or less. Good standard size stock crank maybe 50-100, rods 50-100. Pistons arent worth anything as they rarely are reusable(maybe 25-50).

You can use the rods if you do a 393. For that all you need are 302 pistons, 351 rods, and a 393 stroker crank.

Have fun with the roller block Windsor. They seem to be kinda hard to find.

Something I forgot to mention is that the value of your parts is also affected by location and just simple timing. Those guesses are what I personally would expect to see the parts go for here in CA or on Ebay.