I'm with HotRod. Do a 5.9 with Magnum heads and you'll never regret it. My '72 b-body now has one with iron x heads, KB pistons, roller cam and lifters, small stall, 670 Quick Fuel with a normal belt drive set up and that engine yanks that car around effortlessly. It revs so quick and gets to the power range instantly. It is a a blast to drive even with 3.55 gears. I just don't think I could be happy with a built 318 period in a full interior and factory chassis car. My experience and

‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500