How far to rev this 273 commando build

Video..................Listen to this dartcharger commando I owned a few years back. This engine revved to 7000 all day long . It was tired and smoking badly with 74K miles . All original 273 except I installed dougs headers ld4b duals dynomax ultra flos x pipe 2.5", pertronix ign with a dist curve . This engine screamed ! at one rev in this video it was at 6500 rpm easy. and fast . trimmed smoking bad reving