Right on the 1.920.
So, for the OP, if it has original pistons, there are some decent options, depending on budget. A 0.040" gasket, your favorite closed chamber head (915, or any of the aluminums out there) then fine tune chamber volume/cam to the best outcome.
And if it has the typical rebuilder variety...... It's time for the hard decisions.
Using a 1.848 flat top in an uncut block with a steel shim gasket and the normal 88cc open chamber head, puts you in the 8.0 cr range.
That's going to limit how much cam you really want to stuff in there.
