1966 Barracuda Speeding Ticket

First question is are you dealing with radar? Or was he just making a visual guess of your speed?
I believe you're not going to have much to back up your claim if you're going up against his radar gun. You can always claim his radar gun may be out of certification due to too much time between calibrations but this is really thin ice. My son just tried that approach in traffic court a couple of months ago here in SoCal and lost.
Good luck with whatever you decide to try - but I think you'll be time ahead by just paying the fine.