the 450 castings were used on 262 267 and 305 engines, they have real small ports, valves and chambers, while they would shoot your compression way up there, the extra compression isn`t gonna make up for the loss of flow rate compared to the 882 casting, if you want to kick up compression with the 882`s, I`d suggest getting them milled about .020 and use a GM head gasket with .028 thickness, this should put you right in the 9:1 area. anytime you need to check up on a set of head castings, use this link
http://www.mortec.com/castnum.htm
[ May 03, 2003: Message edited by: DoubleVision ]</p>