GPS sender for speedometer

The vehicles I was speaking of were not A-bodies, so you'll probably find something different under your dash pad. But otherwise, yes, the pad itself will not block GPS signals; it may attenuate the signal strength slightly, but not enough to cause any problems. But covering the antenna with metal is no bueno.
Gotcha. So if I choose the front I was thinking of maybe center dash butted up against dash pad or close to it and should be able to get the wire from there to inside the dish fairly easily. Thanks again.