ok guys i heard something today. one of my friends was told that with his 406 a technician told him to run 1.5 ratio rockers on the exhaust and 1.6 on the intake. has anyone experimented with this or heard of this. the head he's using are the dartiron eagle 200's. the cam is the isky 292/292 duration isky .505/.505 lift. thanks.
This is done often if the piston to valve clearance allows it. If your friend has the motor in his car and has been running it, maybe the machine shop that did the work on it gave him some specs on the motor that included piston to valve clearance. I sure would want to know that before I put 1.6 rockers on the intakes.
U can probably get by with 1.6 ratio rockers on a stock engine, because you usually have clearance. but with any cammed up engine the lift is usually higher, and increasing that travel with more push on the rocker is bound to smack the piston,