Had my old 426 Hemi built to 1973 prostock spec, ran it to 9000 once and 8800 numerous times (Jones-Motorola mech. tach). Torque below 4500 was low. This was with heavy TRW pistons, Nascar rods, 4-speed, R290 and triple springs. Street use only, finally a rodbearing let go and took the Kellog crank journals 5 and 6....