'84 Head/Exhaust Manifold Questions
 

I'm having a difficult time finding an exhaust manifold that's compatible with my vehicle. Each time I come across a pickup at the local junkyard, the motor seems to have already been cleaned out for the parts I need (exhaust manifold, and other smog related parts). I was wondering, if I would be better off (if possible) switching the 84 head for one of a later model, in which these parts are easier to come by?

What month is the truck made. Is it the original motor? Mine is a March of 84 and cannot put a layer model head on. Was told the pistons will slap the head. U can tell what head u have by the exhaust ports. I believe later heads have a pear shape while earlier ones will be 2 holes.