sheared woodruff key on crank pulley

[AV8oR]

Hi guys!
 
Patient: 1987 4KQ w/ 152K on it. 
Project: Timing Belt (now Timing Belt from Hell)
 
Looking at the harmonic balancer I noticed that the driving belt
sprocket (timing belt) had a sheared woodruff key.
After further inspection of the crank, I also noticed that its notch was
damaged (about a 1/4" of the left wall is chipped away)
(the previous owner explained, " it has intermittent compression - it
doesn't run" )
The harmonic balancer was definitely loose due to an improperly torqued
CRANK BOLT!
 
Today I found another Driving Belt Sprocket.
 
My question is - can I just use the new Driving Belt Sprocket w/ the
intact Woodruff Key on the slightly damaged crank or do I have to get 
a new crank? Are there any alternatives (like building up the wall with
J B Weld or a real weld)?
 
[ All this after I broke the Idler Pulley Bolt off and I had to remove
the oil pump, pan and sub frame to get to it.
... oooh I had to reinstall the Cam and Crank Seal twice because the
casings were bent to hell and damaged from 
the previous installation - SIGH ]
 
Any pointers and recommendations are greatly appreciated!
TIA & a Happy New Year!
 
Zaf
 
PS: Can't believe that I spent Christmas Eve and Day Working on this
thing. 
        One less 4KQ in the Junkyard!