Interesting solution to hood clearance trouble. Stick on a cowl induction style scoop then cut a hole in it.
I rather thought the GT's came with a 6K tach. I also thought that when Holman-Moody built an engine for you, you got H-M valve covers too. Not the old corner speed shop M/T covers.
I am curious to know where the rear louvers came from. I don't think I've ever seen any on a 68 before. Interesting look.