I think there are bigger oversizes available. If you have a 74 with original
rods (an 8-bolt engine) the B21 standard pistons will work OK.
If it is a 6-bolt engine the B21 pistons won't work.

In any case you should be able to go to 0.040" or even 0.060" but may have
to use non-OEM pistons. Sealed Power 2015P pistons are standard at about
3 9/16" or so which would amount to an 0.062" overbore. You have to remove
the small end bushings and hone the rod-end to a shrink fit for the wrist
pin, which is bigger than a Volvo piston. This is not so big that you would
have to get a big-bore headgasket, either, which is a problem if you got to
2130 cc.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma