automatic 4 speed is slow to shift.

hey, ive got an 87 automatic with a 305, it has an edelbrock carburetor, its slow to shift, it will climb rpm to about 2500-3000, then it will. Now ive been confronted with something new, i went to cruise yesterday and once it got into third its like it didnt grab the gear, it was like i was in neutral, hitting the gas would just rev the engine...any ideas?

it's slipping. you may need a rebuild. but try the basics first, check fluid level, it could be low. may also need to change the filter. a TV cable adjustment may also be in order.