While I was at the GM Heritage Center looking at the '54 truck information, I looked at the '54 Corvette as well. It didn't list valves spring but said the engine was pretty much the same as the truck except, lifters and three carburetors.

Here is the '57 parts manual listing,
http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0138.htm

It shows Corvette's using the longer 2.250" springs.