[TenTec] Hi power Ten Tec ant tuner swr drift?

[denton]

Hi all...
I have recently purchased an old Ten Tec L network ant tuner..the one that was in kit form many years ago.
I have noticed that when feeding it to a 22 ft elevated ground plane on 80 meters (yeah I know, really a mismatch) via 450 ohm twin lead that the swr will drift on 80 meters and the 2 kv ceramic caps on the cap switch will get really hot...
Will switching the caps to transmitting micas alliviate the problem??
Bad switch??
80 meters on this particular antenna apparently is the only band this occurs with this transmatch...my 238A does not exhibit this little problem when feeding the same antenna.