You have to match what you have with the flex plate...
They come in symmetrical and non-symmetrical bolt pattern for the crank..
Then 10" or 11" for the torque converter pattern...
Find what you have and Mancini has them for $16:
Mancini Racing
10" symmetrical:
Mancini Racing Flex Plate
10" offset:
Mancini Racing Flex Plate
11" symmetrical:
Mancini Racing Flex Plate
11" offset:
Mancini Racing Flex Plate