Good luck!!!!! I cant find anything for these sixtys unless everyone doesnt want to part with anything. I know guys that have tractors sitting around rotting away but they wont part with a damn thing!!
Based on your tractor number you have the earlier manifold like mine. Check this link to an ad in our classified section.
http://www.acmoc.org/bb/showthread.php?21775-New-Early-Style-Caterpillar-Sixty-Exhaust-manifolds-for-sale&highlight=sixty+manifold