power it up, factory connector helps, connect antenna, and any good 10 ohm speaker should do..
do NOT turn it on without a speaker or regular 4 or 6 ohm modern speaker..
this is where I found out about it and fortunate I didn't kill the factory radio in the '65
suggest you read this about vintage radio and speakers first..
http://www.turnswitch.com/speakers.htm
heres' another thread on the subject too, good luck
Testing a stock radio?