My World Products aluminum block Hemi is a .250 raised cam block . Standard Hemi block height is at 10.720 and my block is 10.720 . As stated above you need a Jesel belt drive [ $1500. ] or a gear drive about $1000. ] a standard timing chain will not work. On a raised cam block the lifter bores are at 48 degrees where as the standard block is 45 degrees. Stock .904 lifter bore . You do need a special cam . My block has the lifter bores bushed and also spread .200 for a 2" center from the stock 1.800 The block was set up for 4 3/4" crank clearance I have a 4.5 bore x 4.5 stroke = 572 ci. What else do you need to know? except what the hell was I thinking when I started this project.