Yes, a nice looking car. Don't get too caught up in the numbers. If you get your car to perform the way you like, that's what counts. People are always asking me how much horse power my car has, I usually tell them I don't know or who cares- it goes like stink. I do know exactly what the engine puts out, but I don't know what goes to the rear wheels. The 1968 Pontiac service manual has three listed for V8 four barrel Firebird: 400 Firebird 330 at 4800 rpm; 400 HO Firebird 335 at 5000 rpm; 400 Ramair Firebird 335 at 5300 rpm.
The more important number is the torque, that is rated at 430 pounds feet at 3300 to 3600 rpm. You have over 400 lb/ft at a relatively low rpm That's what burns the tires off. On the street, better to have high torque at low rpm than high HP at higher rpm.
I wouldn't change out the intake or carb you have, they should both give you good performance, just as the stock intake and Q-jet would.
As Rohrt says, the HP output numbers are at the flywheel taken on an engine dyno. No alternator, engine fan, engine water pump, power steering etc. The difference in HP from an engine dyno to a rear wheel dyno can be from 15-30%. Don't worry, I'm sure your engine has over 300 HP at the flywheel, but like I said it's just a number. How it performs is what's important.
