One of the 261 engines I have stashed away has its original 850 head. When I build up that one, I'll probably mill it to match the combustion chamber volume of the 848. A little bit of a compression bump and a Melling CCS-1 camshaft gives a noticeable gain in low end torque, without the problem of a lumpy idle and erratic manifold vacuum.
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!