low compression
http://www.hughesengines.com/TechArticles/dunnuckracing440withwhiplashhmc3245bl7cam.php
I know it may be biast as it is on hughes site and it is a 440...(I just picked up a 73 rv 440 block and am looking at options of building regarding the low compression 8.1-1 or so have found some tidbits here and there this one included. it can get pricey and out of hand fast once you start changing stuff in the bottom end..)
as far as 400's and 383's both are good, found the 400s stock compression kills them flat top pistons, but a ways down in the hole cast crank isn't a huge issue like a lot of people make them out to be specially if its a street car.... used a comp xe284 in both mills (383 around 9.5-1) and both would scream, hit 6500 regularly with both and 7000 few times accidentally with the 383. what killed both engines was not running headers off the 452 heads, but I was happy considering running through cast hp manifolds.. each to their own