Please allow 3-4 weeks build time. These 304 stainless steel headers start with a cnc machined stainless steel flange and then connect to our special step design thick wall stainless primaries which lead to a precision machined high velocity merge collector for the ultimate in spool up and power output. With our full porting option selected below, we hand port each header to ensure the ultimate in flow to the wastegate, the primaries, merge collector, and the final transition to the turbine flange of your choice. Flow bench shows 20cfm gain by porting.  100% tig welded (inside and out where primaries meet head and turbo flanges) utilizing a back purge to ensure the ultimate weld quality in terms of structural integrity, flow and appearance. These headers are so strong we do not recommend the use of any header brace. We do however recommend the use of a flex joint and bracing of the down pipe and wastegate plumbing if external wastegate option is chosen. Headers are built to order and include your choice of wastegate flange option. Please allow us 3-4 weeks lead time to build your header with your choice of waste gate flange and also turbo flange. The headers are available in your choice of T25, T3, T4 and V band turbine inlet flange. Our standard header consists of primaries that step from 1.25" schedule 10 (1.442" I.D.)  to 1.5" sch. 10 (1.682" I.D.)  stainless steel pipe. We have found that when using these headers with high flow cylinder heads such as ours, the larger 44mm wastegate is recommended for better low boost control. The 38mm wastegate is sufficient for stock or near stock flowing heads. Sorry, our headers are Not AC compatible.  GTX and G series turbine inlet options are V band.  Turbo oil feed and drain lines are available separately in the Turbo Accessories section.