Failed to pass air check.

On my 1969 C4 air check. I have used air pressure from 35 psi ( will not apply the piston ) to 80 psi. I used Vaseline to lube the seals and a few drops of ATF to try for a better seal. I turned the clutch drums on the stator shaft to try for a better seal ( no better ). Where can I buy new rubber seals for the forward and direct clutch pistons WITHOUT buying a complete reseal kit? And how much more seal would I get with the transmission filled with ATF and in a running car? Poor idea or really BAD idea.