66 gt350 rivet location for pin cables

If you are talking about 1966 the answer is nowhere. The 66 GT350 like the 65 GT350 did not use pin cables. Now saying that it is hard to say never ever with early Shelby's. If you had them it be up to you to proof the provenence at a concours show. If you could prove they were installed by the dealer at the time the first customer took delivery ,they would be excepted. They are a great idea for a driver car. I can't remember how many times I have misplaced the 65/66 klick pins. The cables would be the exception and not the rule.You might have seen them on 65 R Models. The same pin cable used on the R models with the special swivel end was reused for 1967 which is what you must be thinking of.They were frequently misplaced and lost. If your car has them most likly someone got tired of replacing the klick pins and added them.