Had a buddy who built a Cleveland in the early 80's for his 67 fastback. Closed chamber quench 4bbl heads, Bob glidden pistons, custom rockers, .700 lift cam, polished factory rods. Was a dog below 6000 rpm, pulled hard at 7000, insane at 8000 and felt like time warp after 9000. He regularly shifted at 10000. He pulled it apart after 18 years and the only thing wrong was some rod stretch. Car had no street manners and he drove around at 3500 to 4000 rpm.