For your reading pleasure while you wait, below is the original antenna installation page I posted, plus the second page and the 4 "radio" installation pages from my 1957 Passenger Car and Truck Accessories Installation Reference Manual. As far as I know there is little difference/deviation in these instructions from the 1956 model year so it should still be applicable for your truck. Not sure what radio you ordered or what you are planning on using for speakers, but thought this information maybe a little helpful when you get to that point.
