looking at getting some nice shiny headers for my 350 build. saw these on ebay and want to know what the fourth tube is for that shoots out.

http://cgi.ebay.com/ebaymotors/SBC-G...item4cf233323a

anyone know of a place to get some for around 100 or less. what size should i go with if i am doing a 3970010 block, 193 swirlport heads, and an edlebrock performer intake. going to be carb with a quadrajet.

 

Those are turbo headers and the extra pipes are for external wastegates...