ab1;119807 wrotecan't say for sure as Im not the one who's installing but if it happens again these points will be raised. unfortunately its ruled my 164 out of benella :(
Sorry to hear that. (Hope you'll be there to collect your sway bars though).
Use of genuine welsh plugs from Mother Volvo herself is highly recommended.
Also
http://www.turbobricks.com/forums/showpost.php?p=5275730&postcount=5
Plus - US experience has shown the blocks squirm at high RPM, which will pop the plugs. The big six has a lower rev limit than the four potters. Plug retainers are recommended, e.g. the screw and washer method by John V., as shown by an example of some other gadget here.
See the washers overhanging the freeze plugs?
Probably easier to drill and tap some little holes than all the other genius stuff folks here are suggesting.
The a little allen screw and the right size washer and I'll betcha a nickle the freeze plugs won't walk out...