That's correct, not just the engine. More HP means stronger clutch, U-joints, rear, axles, suspension, tranny, etc. You won't outrun anyone with 500HP under the hood and a twisted driveshaft beating the hell out of the bottom of your car. Why not just match gears with what you have, enjoy the ride and take the racing off the street and onto the track?

I think most Pontiac engines can be woke-up with moderate changes for a more enjoyable ride without going hog wild. Why not contact one of the crate engine guys and tell himm what you are looking for and get some recommendations? I've found one guy just as helpful when I needed a distributor gear as another when I needed a rotating assembly.
I didn't plan on making more power and spending all the money, it started as a rear seal change and the guts were so trashed I had to re-build. I was happy with the car 150HP ago. But, [censored] happens.