I`m making a pair of stainless `J` tubes out of 38.1 diameter stainless tube ... i am short two original castings that bolt to cylinder head ( i did think about making 4 stainless ones but its way to much work for what it is ) must be original VW ones not repro ..... i also can`t decide how i`m going to affix the stainless tubes to the casting . Originally they were brazed of some sort so i may well do that or maybe silver solder (think the melting point of silver solder is lower that the temps seen on the castings ?) or weld ...... bit of a faff as the tube is bigger but thats what i wanted ...... any ideas what temperatures are seen straight out of the head ?