Let's see, stock bore with aftermarket pistons? 273 and 318 rods are the same. No need to rev any Mopar small block to 7500+. They make torque. A d4b won't bolt to your heads and if or the 273-4 manifold isn't the optimum intake for 8,000 rpm. There's 10+ pages of 318 build information. Study up and get back to us.