Lack Of Power

This has been a problem since i got this car......the carb was bad so i just replaced that.....now the car will idle fine, free rev fine, and will drive fine, BUT it has no power at all....you can floor it and the car wont pull past 2800-3000 rpm.....I have checked the timing and it was on, the vacuum advance is working the car does have valvetrain noise on the top end...so the next step should be check the valve lash? or do you think the timing could of jumped in it? Im looking for any advise possible at all any ideas throw them at me.
FYI-Its a 170 from a '67 Plymouth im working on.
Thanks