Mar10n

When people say like 1 3/4 or 1 7/8 header size. Is that the inside or outside diameter?
ID sounds most reasonable, because the inside dia will depend on wall thickness if it was UD. Just want to be sure before i order som tubing..

Thanks

ramairJP

iTrader: (3)

The tubing size is the OD

Mar10n

hmm seems a bit strange to me. is there one standard wall thickness thats used then?
if not, then there could be different ID on the headers..

TooLateVTEC

iTrader: (2)

I think some companies use ID and some use OD.

I just went to Hookers website and they use OD, but ive seen the ads on ebay for the knockoff brand headers and theres pictures of someone measuring the ID being 1-3/4".

There isnt one thickness of material used on them either.