sorry
that was steel pipe i,m looking for
44mm od
i know you used scaffold pipe but that would need a a right stretchy bit of hose to link them
les g

1 3/4" tube is 44 and a bit mm get some with a 1.5mm wall and it will be close for the port size.

Any "good" steel stock holder or on ebay link

well s##k my stump
i did a search and did not see that !!!
cheers matey
les g

motor factors sell straight exhaust pipe
in several diameters.
see page 18 of the pdf below

http://www.catalogue.bosal.com/pdf/prelim/pp_exh_buk_en.pdf