Look at the casting Numbers, 461 were 1.94, however there are 461 heads out there that have 2.02 valves. Lots of heads were rebuilt and people went to the 2.02 valves. You do not need 2.02 valves to put a bigger cam in the engine.
The 1.94 heads will perform well enough with a larger cam in the engine. For some reason beyond my comprehension, People think that you have to have big valves for performance. You don't need those for a street engine.
Unless you are constantly running your engine at 5,000 RPM, you won't see any significant change in the performance of the engine with the larger valves. A word to the wise, some of the early heads did not have a port for the water temp. sender, If you have heads like that, be sure to get an intake manifold that allows for the temp sensor.
