I have just got a 1990 Chevy truck with a 2000 vortec motor it has a new intake but the same throttle body my question is every time I step on the gas it bogs like the old carb motors sometimes did it has a hesitation to it on take off its only when the rpms are low

A hesitation such as the type you describe is usually one of three things :
Insufficient fuel pressure
Bad Throttle Position sensor
Bad vac hose to MAP sensor or bad MAP sensor
If these are OK check your ignition timing.
Does your check engine lamp work? Is it on? You can get flash codes by shorting pins A-B in your Diagnostic link connector under the dash.
You should be able to get your hands on a factory service manual at your public library or an aftermarket manual at an auto parts store.