headers for 340 stroker

who makes 1 7/8 headers and how much ,i know this sounds dumb but do not want to spend 700 $ for 10hp

Look to Hedman.
Yes, headers are expensive, at least the kind of headers where you actually make power from. Real headers cost money. Custom headers should out perform OOTB headers and will cost 3X's the price easy of those expensive $700 headers you want to avoid.

The best header for you and the compromise are tti headers into a 3 inch exhaust.
It will perform well.