[keynsham1]

I have a 911SC and I have just installed six of my rocker shafts. when tightening the through bolts it was noticeable that although most became very tight in the bore very quickly such that holding the nut end was not required, whilst others needed the nut end to be held right up until the bolt was torqued up, otherwise the whole rocker shaft would rotate. Is this normal?
I would have expected that if the coned ends were expanding the shaft ends out to make a seal, then it would clamp up in the bore quite quickly.