A high quality oil pan is a must--Charlies comes to mind--the deeper the better as the 408's can and do act like a blender with crank case oil--run as little oil as possible ( I just don't think you need 7 qts) run six or less.
Some can hit a standard dipstick, be sure and check that during build.
Vent valve covers well and keep breathers near the front for sure.
A good one feels like a big block, you are going to have some fun! I agree with Wise, they likey some good heads--do not skimp on rocker arms--get some good ones.