LS1 Down and Forward Turbo Headers. Header flanges are made with 3/8" thick 304 SS and tubing is .065 wall 304 SS with 1-3/4" Primaries and 3" Slip Fit Collectors. Headers are fully tig welded and back purged. Can be used with factory A/C. V-band Flanges and EGT bungs can be welded on as requested. Smaller 1-5/8" dia. tube size and 2-1/2" dia. slip fit collectors are also available.