Hi,

I use a Garmin ETrex Legend and mount it on a cellphone holder on the
instrument cluster between the speedo and tach on my 87.

On my last road trip to Key West, while my kids were driving, I sat in the
back with my GPS sitting on the table next to my laptop (running Delorme
software). I didn't have any problem loosing signal through the fiberglass top.

Ric