the 500 cad engine has a longer stroke, more torque,less h.p. i went with the highest h.p. cad engine. 1969 eldorado 375 h.p. 500 ft lbs torque. i share rent of a garage with a caddy freak. he had a bunch of 500's, 472's, 425's 368's sitting around. at first i was going to make a short stroke cad engine using a 368 crank but it has the same stroke as the 472, less bore. this engine is only 100 lbs heavier than a small block chev 625lbs. i hope to have it running this week. i'm just on my way to get my gas tank back from refurbishing. i,ll take more pics today.