Hi so i Bought a 1987 camaro z28 305 ho. been sitting for 4 years started right up drove it home. On the way home i noticed it was slipping and didn't want to stay in overdrive at all. drove it a little bit maybe 25 km the next couple of days and tonight i put a new filter in the transmission. I thought it fixed it as it was shifting in all 4 gears for the first time but onces it warmed up it started slipping and got worst and worst and now the fasted you can go is about 50 without reving it all the way to 5000. I am new to camaros but can do work myself any help is appreciated. Also what transmission would i have? a 700r4?

P.S first gear works fine and it swings the sweetest tight circles youve ever seen.