I think the 409 or trips idea is strictly up to the owner. Everyone has their own ideas to make their truck what THEY like. There are a few 50-53 trucks running around here with 409's in them and the fit just fine and run like a bear.

Retired Military, Six years Army, Seventeen years Air Force
Army Security Agency High Speed Morse Code Intercepter
Rigger C-130
Master Sergeant 32nd Aerial Port Squadron
Commander American Legion