I keep thinking that improving the 5.9 is the way to go. Block and heads are proven. Don't have to swap out the k-member and suspension.
I got a quote from Hughes Engines a couple of months ago for the stroker kit (425 hp/475 torque) when I started thinking about it. As a way of a competitive quote and second source for the entire SB stroker kit who would be a recommended vendor?

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