Welding Tips and Tricks

hey guys.
which wire do you recommend for tig welding 304 sch10 1.5" pipe to a mild steel plate\flange? its a high heat application (turbo manifold) and will spend most of its life in the 20-900 Celsius range?

iv read in some places that 309 is good for high heat, max temp of 371c?

thanks

309 all the way. It's specially designed for welding stainless steel to mild steel.