...I've never changed jets before....was wondering do you just unscrew them with a standard flat blade screw driver? Or is there a special tool needed to do the job?

A flathead screwdriver that fits snugly in the jets will work,you don't want to nick the jets,they say it affects fuel flow.

You will also have to readjust the pump or pumps if its a double pumper.

This one is a vs carb. 4150 series.

But seriously you actually have to readjust the accelerator pump when doing a jet swap? How so?

when you pull the bowl, you will not put it back in the same place. Remember, we are talking about .005 of an inch give or take but it will be enough to cause problems.

The Gaskets have a groove in them from the float bowl, put the float bowl back on the gasket and gently wiggle it around until it finds the groove. ( don't forget to swing the accel pump arm around first), You shouldn;t have to reset the pump length when you're done, but check it to be sure.

I use a cut open soda can under each of the lower fuel bowl bolts to drain the bowl of gas (if its on the car).