under rating the hp is fine. It will just be an added bonus when you make more power. But it's not ok when your building the rest of the drivetrain. I would hate to see someone think they are going to make 500hp ad build the trans and rear end to handle 500hp, and then find out they are making 750 or more and end up spending more money to fix all the broken driveline parts. Build it once and have it dependable that's what I'm trying to do. I just got most of the components for my fuel system and it should support way more power than I could ever want. Why so that I don't ever have to worry and not haveing enough fuel as upgrades progress down the road. Over build everything. That's my plan.
on a side note. It appears that currently we are the only 2 that are building modern hemi twin turbo a bodies. (i could be wrong but I have not seen any others) and for that reason alone we stand out from the crowd. So I can't wait to see how your build come out. Reguardless of thepower levels. We can benchtop race all day long in the end the parts that we buy will end up telling the story.