I believe the compression drop was done by using dish-top pistons instead of the flattops used in the original 292. That's a drop-in change on a rebuild- - - -just order the early piston. The bore size, connecting rod length, and piston compression height will be the same. For even more compression, if you're building a low-RPM torquer engine, find a cylinder head for a 194 inline six and do a little porting, then install bigger intake and exhaust valves. The 194 head has a smaller combustion chamber, and combined with the flattop pistons, it really bumps the compression up. Use a Comp Cams "RV" cam if they make one for the 292. High speed performance will suck, however, because of the restrictive ports. If you've got deep pockets, do the "lump port" modification to help high speed breathing a little.

As always, "There's no substitute for cubic dollars!"
LOL!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!