If you want a fairly inexpensive way to bump up the CR on a 292, milling the head will do it. Another way that's not very expensive is to use an LPG piston, which will give a 9:1 CR to a stock 292.
LPG pistons for the 292 have been out of production for a while now but I checked a local Autozone about a year and a half ago and after making call after call (and more calls) he was able to track down a set in some warehouse. About $200/set I believe. The only option was .040 overbore and I recall the part number being 980P (Federal Mogul). They'll pop up on Ebay from time to time too.
-magic mike-
