Lookin' to buy headers for my 302 in my 1989 f150. I noticed while i was lookin on jegs that all the headers they offer for my truck say for automatic transmissions only. Why does it matter. also what brand do you guys suggest?

 

There can be some linkage problems with Manuels and headers. I got the headers in my car from Jet-hot. they have Hooker and headmans available for your truck probably.
http://www.jet-hot.com/pages/Precoats/FordTruck.htm