I have a sears furnace model #867736337, furnace work great but now the blower fan broke. Sear's dicontinued the part, where can I find one or were can I located a center that carries discontinue parts.

You may have to find one that will work for what you have.
This will be a matchup appearance type thing. If you have a local
Johnstone Supply
OR
WW Grainger.
Also a local HVAC company should be able to help you.