Does anyone know if the 964 engine through bolts suffered the same shortcomings as the head studs?

Are 993 through bolts better than the 964 ones?

Thanks in advance

 

I don't think I've ever read about thrubolts cracking. The one issue I do recall is that some of the blocks were mismade and need paired orings on one side to seal correctly, and also that frequently people will add a chamfer to the area where the orings sit to help them seal and prevent infant mortality.

There's a TSB on the first.

 

Never seen a problem with the through-bolts.