What to tell the exhaust shop.

I found a shop not too far from my house that will install a custom exhaust system on my 225 Slant 6 1964 Dart GT. None of the chain shops bend pipe. This is what my setup will be. Aussiespeed Hurricane intake with Quikfuel 450 CFM Black Diamond Slayer 4 barrel, and Clifford Shorty headers. I have been doing a lot of reading so here are my thoughts. 2 inch Y pipe under the hood to the drivers side. Have them install an oxygen sensor port at the end of the Y pipe in case I upgrade to fuel injection at a future date. From the Y pipe 2.5 inch diameter to a Flowmaster 40 single muffler with a 2.5 inch tailpipe.

If anyone has any better ideas, bring them on!