ok in order to to read your private messages you click on notifications just like you did ..in order to send one you click on their name and then view public profile.
there are alot of places you can buy parts for these old trucks but your best bet is on these blogs. your in luck because you are choosing to keep your six cyl, where as most are looking to upgrade, so you should find one cheap..
get a shop manual for your year truck.. the 223 was a good motor used in lots of applications so finding one if you recognize it are good..
try pick and pull junk yards ..i have a 223 with a hole in the block so manifolds are spare to me, shipping is going to kill you. try to find one local, and as a last resort weigh yours, and check in to shipping costs.... you can also reach me at
jdrp@sbcglobal.net and put "223 manifold" in the subject line if you need more help always glad to help if i can