how large are the stock valves?

[soundguy]

curious about the heads on my car as I haven't had it long and still trying to find out all that has been done to it in past. I've seen others saying they had the heads redone with larger valves. On mine, the 2 valves are so close there is no possible way to put a larger one in them. The cuts for each valve just begin to over lap and the gap between the valves themselves is maybe 1mm 2 at most. Am I correct in assuming they have probably been up sized at some point in past?

 

[buickpower]

its possible. the stockers were 1.71" and 1.5". often the bigger ones people put in are 1.77