Oil mods for my 408?

AMC lifters can oil through the pushrods. You just need hollow pushrods. You can use the AMC pushrods with no ill effects with standard non oiling pushrods. No mods needed.
The stock oil passage ways are good for 6000 rpm easy. Pushing past it starts to get dicey depending on how it is equipped and the internal passages are like. I have not ever had a problem @ 6500. I have had a problem @ 6800.