The key to the all motor build up is experience.

I've yet to find anyone doing any F-series work. The key to any good NA package is the compression and cam.

If your building an F23 (gen6) then I'm not even sure about the pistons but custom unints shouldn't run you too much more then standard forged pistons.

In addition you'll want to fully balance the bottom end of the block. This helps alot since RPM is the NA's friend you'll need to fully balance and even lighten the crank some to help. Billet rods likely will only help in the balancing department as the stock rods should take plenty of NA abuse no problem, but they may be harder to balance up w/ the the crank. But I don't see that as the issue either.

The kicker is the cam--no one makes a new cam for the F-series. All cams are just regrinds which will tend to suck in IMO. Crower offer hardfacing but its not recommended for a street engine.

I would be building a killer NA F-series this winter but the cam is a major issue for me. Not to mention finding anyone that knows how to port an F-series head is nearly inpossable as well.

Gude quick return my calls or e-mails so I figure I was asking too many questions that they knew I wouldn't like the answer too.

Good Luck and let us know if it turns out.