Great stuff! I was surprised to see that the Buick aluminum-block 215 cid (aka Rover 3500) had the
same external dimensions as a small-block Chevy! Gotta have room for those cylinder sleeves, I guess.
Not quite in the same category, but I find this handy:
Engine Cubic Inch/CC Displacement Calculator--
http://www.csgnetwork.com/cubicinchcalc.html