You couldn't make the 292 piston work in a 250 engine at all. The compression height is too far apart on either to make it work. Also, like Tom said, any standard off the shelf replacement forged piston for a 250 isn't going to have the ring package placed on the piston to be suitable for turbo use. The pistons for his 250 dyno testing were made for the turbo as the end goal, and were moved down the piston to accomodate that useage. You could probably use a Loc-wire style head gasket and be fine without o-ringing, but with only 4 head bolts per cylinder, its a fine line between safe and not....
