This adapter bolts to any 79mm Holset v=band exhaust flange and accepts both Ø2.5" OD and Ø3" OD tube . The 2.5" tube will insert into the adapter. The adapter has a Ø2.86" OD, and 16ga 3" tubing will slide over the outside. The flange is steel and has a recessed bore to give you plenty of material to weld to.
 
Kit comes with:
-Cummins Steel V-band Adapter
-Cummins 79mm V-Band Clamp
 
Preferred TIG filler for mild steel tubing is ER70S6 and 309L for stainless.