I did that on a 406 sbc, it doesn`t need that large of coolant lines. I did the rear crossover thing on it also. I thot about doing it to my 505" wedge , but haven`t really had the need for it so far.
The lines I am going to run are #16 an or 1 inch. That is the same diameter as stock and matches the same area as 4 1/2inch cooling holes.
Although I did not mention it I am planning on running rear lines to the manifold
