rhoads lifters?
Well the rhoads were designed for crutching a big cam on the street when lobes were very basic,you got more torque and better idle/throttle response on the street with the higher bleed down rate of the lifter at low rpm,but around 3k or higher they are fully pumped.The newer agressive profiled lobes build more cylinder psi down low already to give you better vaccum/driveability and idle,so when you combine that with the rhoads lifters you run the risk of creating too much dynamic compression and detonating.Also since the lobes are more agressive the rhoads tend to make alot of noise,if your starting from scratch your really better off to pick a modern cam with the right rpm range to begin with.