74 B-body headers

[LargerCharger383]

I have a '74 charger, but the 383 engine is out of a '69 roadrunner.  I can find some headers that will fit both applications seperately, but I was wondering whether there were any major differences between shorty and full length headers, and how hard each is to install.  I've heard a lot of different things from a lot of different people, but I figure this site is the most reliable way to go, Thanks!