440 motor in 68 Barracuda

If it were me, I would probably use the Schumacher Tri-Y's as
HemiMark suggested. I believe that these are extremely easy to
install, reportedly even with the engine in place.



Schumacher is also in the process of releasing their new under-
chassis version of the Tri-Y's.



The factory LH side manifold was flattened to the point that it
strangled the engine, costing significant horsepower.



If you insist on the factory look, a company called Accurate
LTD makes a modified version of the stock manifold that flows
very well while retaining the stock look up top.



They also have a 3" Max-Wedge style exhaust system that
mates up to their manifolds, complete with cut-outs. Lots of
nice color pictures on their web page.

Link:

http://mysite.verizon.net/vze8el3i/id13.html

Accurate LTD comparison photo: