exhaust pipe

Fabricating exhaust. From "D" shaped exhaust port to round.

Gentleman, For sale is my NOS Taylor Spark Arrester muffler. The muffler is like new and never used. It is complete and measures 4" long and fits a 1/2" pipe thread. I want $65 shipped through UPS with tracking information I'm in Duarte, CA Payment through Paypal Muffler on my Tecumseh...