I checked in earlier with our 1969 400 4 spd GTO. It has junk heads on it and a two barrel intake. Obviously the original engine is long gone. I see locally there is a 1971 455 YC short block with casting 66 heads for $500. Would this be a better route than beheading the current 400 and finding more appropriate heads and intake for it? I don't want a pooch, but don't need to be the fastest car in town either. I want something that fun to drive with enough oomph? to scare the new mustangs and cobra's running around here.