Regal Canadian speedometer reducer

I'm trying to locate one of these canadian reducers Gbody claims will let me insert in my speedometer cable to use their 145 mph speedometer overlay. It's for a 1985 regal. Thanks Roger

 

GM used them on many cars and some trucks...not hard to find.
You need to determine what ratio you need.....most common is 0.8241
and 0.7333

 

Thanks for the info. I'll check with my local Buick dealer and see if they can come up with one. Roger