I’ve never seen factory published data but my factory tach (Cutlass, not Jetfire) shows redline between 5400 to 5600 RPM. I have an old Hot Rod Magazine article on the 215 from a special magazine in their “Technical Library” called HOT RODDING The COMPACTS. They did some tuning and some easy bolt-on component replacements to see what kind of power they could get from the stock engine. They experienced valve float at just over 5000 RPM with the stock valve springs. The factory specs. for the Jetfire engine are peak horsepower of 215 at 4600 RPM and peak torque of 300 ft lbs at 3200 RPM. Later today I’ll try to post the Hot Rod article. It’s very interesting. There’s also an article on the Jetfire & Corvair turbo engines that I’ll try to post as well.