IF you were really serious about getting BIG inchs out of your small block, you could add to the deck height with --for lack of better words but it paints the picture well enuff,--- adding height like a torque plate welded on.
This extra deck height would allow a MoPar crank to be cut down for use of a Chevy rod adding more stroke. OH and longer rods.
IF you can add height, the next issue is bore size.
Bore size has a limit. How far can a race block go before it's too late. Add block filler for stregth so you can bore farther. What is the max?
NOW! Who has money to throw at this problem? Anybody have an inside to goverment funds? HEY! If they can spend $500 on a hammer back in the 80's..........