Elgin Industries makes a replica of the 261/"Corvette" cam that works very well as an upgrade without getting into manifold vacuum problems and a lopey idle. Yes, you'll need new lifters (solid lifters for that cam). No, roller rockers aren't available for stovebolts, nor are they needed. Stovebolts can't turn enough RPM to need exotic valve gear.
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!