Are you sure you're not thinking the Telemaster 40? Way back in the early 80's I had a very strong O.S. 40 with a Mac's pipe on my Telemaster 40. It was fast as hell for a "trainer" when I wanted. Only problem I had was I usually had to land dead stick or it would float to the next county if at idle even with the flaps down. I haven't had a TM Senior though. Maybe it has a weakness somewhere?
My present TM 40 will be electric if I ever get around to covering it. I swore off slimers a LONG time ago. More power and less mess and smell when electric......
Joe