lifter rattle ? > what weight of oil are you using ? if it's too thick oil won't get to the top of the motor > my motor make's a ticking noise some times not something I'm real woried about > is it a spark knock ? have you had it tuned for 93 octain and running 87 ? are you sure it's not a header leak? only other thing I can think of is the possability of a bad or broken roller rocker