Do you think the rod's length has any effect on the displacement?
The rod length and the deck height has NADA to do w/how much crank physically fits inside of a production-based BBC block- be it pass. car or TD.
A TD BBC will not make a bigger engine than can be made from a passenger car-based block. All that would be different is the rod/stroke ratio.
"Pat Musi, a long-time East Coast engine builder and racer, specializes in 555 cid big-block Chevys for everything from street cars to hardcore drag racers weighed in on the short- versus tall-deck aftermarket blocks this way. "Ideally, in a race engine you'd like to have a 1.8 rod ratio. A stock 427 Chevy is 1.6. With the 4.25? stroke crank that we use in our 555s the rod ratio is around 1.55. We just live with that instead of going with a tall-deck block because I prefer to keep the rotating mass low, and I want to take the flex out of the valvetrain.""