I'm pretty sure small block Chevy V8 valve springs and rotators will work on a Stovebolt. The exhaust valves are identical, so I can't think of a reason the rest of the assembly would cause any problems. The intake valves don't need rotators. I just happen to have a couple of heads on the workbench right now, a 261 head with rotators, and one for a 350 V8. If the incoming severe weather that's predicted for tonight and tomorrow doesn't blow me away, I'll be happy to make some measurements and post the results soon.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!