Some up dates. I've heard from people that the reason for the squeezed sides is to match the square bores of the head so, no worries there.
I'm going to keep my headers but, build/buy new 2" J-tubes, collectors 4" muffler housings, 3" mufflers and tips.
The KC engine is a go, the EFI sadly no. By the time I bought both and completely running, the cost of apx. $15,000- $20,000, is too high for me.
But I know I'll be very happy with a nasty, high HP/TQ Keith Craft aluminum 427 side oiler.
Now we can talk details.