Picked up a low mile 1974 472 for my International Scout. 
Now I'm thinking about putting 425 heads on it. Supposed to be worth 40 hp, but not sure about the torque. And better thottle response I've heard. Is this a good idea? I'm looking for all the grunt I can get between idle and 2500 rpm.
What mods would be necessary? Drill steam holes?
What should it cost for a valve job if I find some good used 425 heads?
Thanks....
Now I'm thinking about putting 425 heads on it. Supposed to be worth 40 hp, but not sure about the torque. And better thottle response I've heard. Is this a good idea? I'm looking for all the grunt I can get between idle and 2500 rpm.
What mods would be necessary? Drill steam holes?
What should it cost for a valve job if I find some good used 425 heads?
Thanks....