[Oldsguy]

I'm not really sure about the resto rules. Those guys might say "if it wasn't on the build sheet it shouldn't be on the car" but I would think if you could find a correct posi for that year and model and it was available then go for it. If you replace the exhaust manifolds with headers just save the manifolds and then you can put them back on if you ever sell the car or just sell them with the car. It is true that a restored car will probably bring more in resale than a souped up hot rod unles you are making major money at the races with it, and even then it would be doubtfull. But, I say do them both!! Go for it.