What are a good valve size for a cc503 cam?

 

Let the guy porting decide what he likes to work with. If not porting then don't bother with valves. Some LT1 specialists like 2.00/1.56 some like 2.02/1.6 but they require more work.

 

I am thinking about picking some heads up with 2.02/1.6 valves. Will that be too much for my cam? I have the CC503 with 1.6 rr?

 

Depends on the porting more than valvesize. I wouldn't say 2.02/1.6 is bad but DO NOT mistake bigger for better. Better is better, bigger might play into it but if the guy grinding was some ignorant hack he could make the heads flow like crap with big valves.