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: