I found my plastic battery tray is cracked at the back where the cleat holds
the battery in place. Question, is this made out of poly, as I know a guy
with a poly welder and so we can try to repair it.
Or if I need a new one, is there a source besides GM.
Thanks.

 

Napa auto parts has them

 

You can replace it but the new one will fail the same way; they haven't enhanced the design. I bought a universal "J hook" battery mount and slightly modified the existing holder to secure the battery.

Another good solution can be see on this link (view post #7)

http://www.ls1.com/forums/showthread.php?t=60554