The cranks are really stout. Don't use the later model external balance unless you get the flex plate & damper spacer. I have a 75 pass car crank in mine & made 750 on the dyno on the engine & another 400 with nitrous. The rods aren't bad but about 550/600 is max. The main things to look for in rods are a football shaped rod bolt & a truck part #. The latter being a little better around the small end.