So this is the same kinda question I enquired about on another thread.

So if you had some running 420s in need of a light rebuild what would you do for the bang for the buck.?

1st could you go with a Madera cam and open the heads up a little bit and gain 50 horse ?

Or would you slap a blower on it maybe with 2 carbs to get the airflow?

Or upgrade the heads to some AFRs and than call Bob and have a cam ground?