I looked again, and it does appear that you have an aftermarket Crank Pulley (and therefore had a NON-STOCK idler blow up). If you have can find the pulley in the pan, you should be able to replace the bearing.
If not, send me a note; I have replacement pulleys for that (I have both the ASP pulley that you had and a METCO better quality double-bearing replacement).

Cheers,
Chris
Latemodel21@yahoo.com