You won't find higher gear sets for your original '49 rear, they weren't made.
Your modification options to go faster are;
Install a newer rear that has taller gears.
Install an Aux trans that has Over Drive between your existing trans and rear.
Replace your existing trans with a trans that has OD.
Bear in mind your engine will struggle with talled gears or OD on anything not flat or with any kind of a load.
Mike B
