What is the difference between the two? I am just curious as I can't seem to do a google on the difference.

 

different terms for the same thing...
exhaust manifold = exhaust header

 

yea same thing

 

When the term manifold is used it is normally referring to a cast piece. They are normally bulky and route all the exaust gases to the rearward piping as quickly as possible.

Headers normally refer to separated pipes joined to a base plate and the piping is designed to keep the exhaust gases separate until the optimum time for increased performance.

 

^^x2

Yea, what he said.