ok i found out my transmission has a cable driven speed sensor, the guage is electric, what should i do? get a new transmission (since this one may need to be rebuilt) or get the cable and gauge set and whatever else i would need to do for that swap?

http://tpiparts.net/inc/sdetail/10956/7586

or get the correct F-Body VSS unit to fit in the trans

oh yeah, that will work, i didnt even know they made those

Edit: i was looking at it and i realised it said for tpi and tbi, i have a carb, would that matter?

You have a carb NOW.
It is what the car came with originally that matters ( unless you ripped out the dash and wiring as well ? )
You don't mention what year your are talking about ; different setups for different years

its for my 86 firebird, it originally had an LG4, the last owner swapped the engine with one from 1984 which im assuming is still an LG4. The wiring harness is the original one