Torn between buying the hawks headers or the eBay ones for $320. Hawks is saying that their primary tube is 1 3/4 inside and I've mixed reviews that the eBay ones are 1 3/4 outside. And also, how are the fit between the 2.

 

I cannot verify the fit as of yet, although I am aware of no problems of folks using them, at least until my own engine goes in.

Mine are 1 5/8, but for the price I really don't care, better than manifolds and the Hawks are a hose job and they want like another $450 for a y-pipe.

Some folks have been posting that the new version of them are indeed 1 3/4 however.

Check out the Lt1/Ls1 swap section at thirdgen.org, someone may have posted pictures and measurements of the new version