What cam to use in a 318

I would seriously consider the Chev LS valves that are 1.9" I and 1.55 E. To do this you need 8mm guides. You could use the Chev powdered metal guides or step up to bronze guides. You can use the Chev beehive springs, retainers and locks.
I'll never understand why Mopar guys still use 3/8 valves. What's the length of those valves by the way?