I am running a .510 lift Sig Erson hydraulic roller with Scorpion hydraulic roller lifters in a 505. I had to do no machining of the block and the cam used a standard oil pump drive gear. Used the recommended Erson springs. Have run for 2 years now and around 3000 miles with no problems. Grind # is RH-286-340 and the Erson part # is E419105. Super low end and mid range torque. Barely lopes at idle.
