1960 Valiant - Should I Super Six???

I say yes it will make a difference. It won't be a screamer but it will go faster especially if you fatten up the stock exhaust pipe. You don't have to go crazy with it, just bump it up to 2" or so. I did a super six setup on my 67 Barracuda and love it. Your car is even lighter so go for it, you won't regret it.