Anyone hook GPS to drive the speedo? Per Autometer, they say theirs may but....

[2005_Ragtop]

I have an 2005 GT which I may put a 351/4R70W engine/trans. Gauges are a small issue, considering everything else, but would like to be able to use the speedo and tach already there. Asking if anyone ever used a GPS to drive their speedo....
Thx,
John W.