I am sure my rancho is toast with a dented tube[both of them]and the rancho directions do state up/down.The QA-1 tech on the phone just said the TD901 can be inverted,I am just not sure on the valving being strong enough ootb.

GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/