Otto... I figure as fast as I can hold it in the road comfortably is about 60/65. 2800/3000 rpm or so.
Back in the late 70's with my 51 3100, 216 3sp, I drove like it wasn't mine. Matter of fact, I drove everything like it wasn't mine. Blew a couple of engines, too. Been there, done that, don't want to do it again.