Hmmm. Good question. I know that the 61 and 62 radios are different from each other, as they have different P/N's. Also they will not work with opposite's speaker. Ohm-age was different. I don't know anything about the 63 radios. Perhaps it was the first year for pushbuttons in trucks? There are a bunch of car and truck radio guys on the net. Do a little digging and when you find the right guy, he can help you with p/n's, etc. I think that as long as you had the correct speaker to go with a radio, you could use 60-63 radios, as the dash is the same through those years. They come up for sale on eBay regularly and you should be able to wait it out for a good one.
