I believe all those pieces come in the kit tclederman provided earlier
http://www.chevsofthe40s.com/images_product/large/3701900C.jpgThe spongy seals(top of pic in above link) in the kit go
here and the gaskets with the 6 punched holes will replace
this again the stuff in the kit is not like original, My truck is a 3100, Denny will have better info on the 3600.
Hopefully someone will chime in to confirm or correct
Good luck