Welding SS to cast iron
 

I have a garrett t04s with .84 a/r exhaust. I have a stainless vband kit. I have some 16ga stainless tubing. I need to apply all 3 together. I have a couple of questions:

1. is the exhaust housing on the garrett cast iron or cast steel?

2. how hot should the housing be preheated to prevent warping and uneven cooling damage? 600*F?

3. what rod filler should be used? 100% nickel? bronze? 309L?

I've been doing some searching, and I've seen some mixed options...so forgive me if it's a repeated question

if your using 304L stainless for your exhaust you may find it to not be strong enought for the heat, otherwize you will need 309 filler rod to weld stainless to iron.

I would just take it to a pro welder, it only cost me $50 to do my exhast manifold for my twin setup.

yeah, it's 304L. I thought 321 was more prone to cracking, or do I have those 2 backwards?