<VV> EM, LM speedometer question - add'l info

[Chris & Bill Strickland]

Okay, I need help with my rememberer here -- somewhere in this era, some 
car used a backwards speedo, identified by a reverse twist speedo drive 
cable, and I can't recall who/what it was -- BMC perhaps?  Or was it 
Corvair vs standard GM ?  It was important, because if you replaced it 
with a cable twisted the other way, then things came unwound, generally 
in a hurry.

Anyone know what I'm talking about?

Bill Strickland