They flow equally to a 346 0r a set of 906s. If you were to run a dyno test with all 3 you would hardly see any difference.

Yes the templates will work on all 5 BB heads except for the Max Wedge heads. . I did a set with oversize valves,very mild pocket porting and a gasket match. That made a world of difference.
Just start grinding to match the templates. They are marked for the amount of material to revove IIRC.