How many more revs do you want?
A well tweaked A15 which has the longest stroke in the A series family at 82mm will still happily spin to 8,000 rpm which is quite adequate for most applications as the torque output is good & more revs are not really much of an asset.

Some of the speedway blokes seem to run A12 cranks in A14/15 blocks with special rod & piston combinations. The extra length of the rod allows a more gentle rod angle at about mid stroke & these special race engines can be spun up to about 10,000 rpm but lack the torque to handle a heavier passenger model car like the A14/15 will.