Does your Dart have stock inner fenderwells? If not, you should consider building a 392. I don't think the 392 would fit in the stock A body engine bay. The 392 has a 0.50" taller deck height than the 331-354 blocks.
I realize you already have a 331, but I'm just wondering if you'd be better off building a 392? The cost of building an early Hemi, to only have 331 cubes doesn't seem worth it. You're already looking at custom headers, and motor mounts. Plus, the early Hemis are no lightweights.
