With the cam i've got I change just between 6500 and 7000rpm because thats the power band and i feel pretty safe there with all the stories of people hitting 8000rpm without any trouble. My uncle who is a mechanic rekons that the A series have an almost unbreakable bottom end and I would believe that after pulling two down and seeing the thickness of the crank and rods for such a small motor.

edit: Also my uncle just built a supercharged a15 for this bloke who sent away to america for forged pistons and rods + the crank was shot peened and to date he has run a 12.8 quater on this engine at over 9000rpm

If anyone really wants to know I could get the profile of his head that my cousin ported.