High lift cams mean long duration cams, which leads to very late-closing intake valves which leads to very low cylinder pressure which leads to a sluggish pig of an engine that everyone loves to hate, because it is gonna cost you a convertor and some 4series gears, and she will drink gas like a fish in a lake.
This is generally not 100% correct since this comment ignores the lobe ground on the cam. You can have very high lifting valve with or without additional rocker ratio.
You should pay attention to it though, it’s your fair warning.
Even though it assumes a lot, a real lot! It also ignores and assumes a lot in your behalf. Then again, maybe you want to go there?
Rustyratrod has posted up the tool needed. You can use this in a hand drill or better yet a drill press. Pay big attention to the angle of the bit as it contacts the bottom. Take off only as much as needed to create a smooth even surface as the drill bit is in the guide as straight as you can get it. You’ll be fine.
