broken cam gear key; 034 turbo kit on 7-A coupe

[Tom Egbert]

  Got caught in situation with son needing car to drive back to Kansas City from Indy, here is what happened.   

   While installing turbo kit and rebuilt head ; either key was broken prior t-belt job or it is very fragile, pulled off pulley to put on final time and key was split. It went in and stayed in place and the fit is tight and then tightened bolt to torque spec with stock thick washer in place. 
   Son drove to K.C. last night. Ran great,over 30 mpg. no issues. I told him no getting on it; just drive gingerly until we know the torque is transferred by the fit and clamp of the fasteners or get it replaced.
    Any similar situations? Engineering analysis?
                      Nervous Dad,