Headers ?
Dougs or TTi seem to be the only highly recommended full length headers that fit without much issue. I think some guys are runing Hedman shorty style headers without too many issues.
Do you have power steering and what kind of transmission? It can really depend. I'm about to do a Dougs install on my 340 with power steering and a four speed tranny. I'll try to check back and let you know how it goes.