Anyone using a Gear Venders O/D unit?

I cant offer anything from an experience standpoint. I have one sitting in the garage waiting to go into my '69 Charger. I bought it primarily to go behind my 470 stroker to make the 4:10s more streetable.
My only input is-you could buy a lot of gas for what the GV unit costs. If you want it to tame a set of 4:56, then it makes sense.

I see Old man ray beat me to it.