If your talking about a ford v10...think again. As far as I know the latest versions are only producing 362h/p. Granted torque is waaay up at 457, it's a far cry from 500. I would think that for the price of the conversion and the upgrades needed to get the h/p and tq levels up….you could have a streetable 302 or 351 with similar or better numbers.
Also keep in mind you would probably be adding at least 200lbs of dead weight right where it hurts most. I'd venture to say that if you were to achieve the same h/p and torque levels on the v10 as you were a 302 or 351, the 302/351 would be faster while being just as reliable (properly built).
Sooo….here is how I see the breakdown….
If you want to spend more money to go slower….all for the sake of originality, do the v10. If you out for the performance and bang for the buck, stick with the 302/351.
Here is another thought. Venture over to www.turbomustangs.com and take a look at some combo's there. There are many there that have built reliable turbo setup's on a budget while maintaining "daily derivability". Just food for thought my friend.
Oh yeah.... 500 rwhp is easy with boost. You can do it on pump gas, but you have to be willing to up it a little. If you're seriously considering the V10, just get a stroker 351 or 302 with forged internals, nice heads, and the right amount of boost (depending on the combo and displacement) with any decent turbo setup will get you there. I've heard of guys doing that with a junkyard Turbocoupe twin combination.