Chevy LS1/LS6 Stainless Steel Shorty Headers. These short tube headers are tig welded and made of high quality T304 stainless steel with CNC machined flanges. They feature 1-5/8" tubes with 2-1/2" collectors. Tubes are heavy duty 16 gauge and 3/8" thick flanges. Headers are a direct bolt-on installation with no modification needed. These headers will increase air flow for gains of 10-15hp. Kit includes collectors, gaskets, and bolts needed to install.