That engine never was offered as a performance model. RPM is 4800-5200, anything over that power drops off and runs risk of breaking piston skirts as piston is a crossflow type design
Dump em out quick as the earlier valve had nylon balls and acetone will damage the plastic. Rinse em out with syringe and 50:1 mix the check to see if salvageable
Tis combination of stainless and nickel and is heat hardened at pinion bearing. They snap right above heat treat, just take right rpm and shock to gearing