You really can't go wrong either way, but my preference would be the 66. It would be a prefect match for your 65 coupe! It is classic to the hilt IMO. I have a 66 coupe and am thinking of getting a 66 FB but have yet to find the right deal. I think there are plenty of repro parts for both 66 and 67. The advantage of the 67 is a little bigger engine bay that allows you to stuff in a bigger power plant without any fitment issues. I like the interior of the 65/66 better too. Just doesn't get any more classic that that!