Lambda Boss
 

Just starting to look at doing my exhaust system and I'm wondering how far away should the lambda boss be from the head? should it be as close or far away as possible?

It's usual for them to go after all the branches come together. Not too close to the head so it doesn't get too hot.

its not necessarily about getting too hot , its more the fact you want to monitor the performance of all 4 cylinders or 6 if you have 6 etc. you get my drift :) so as close as to the head as possible but while being able to monitor all exhaust gas.

I mentioned the heat as I have had a wideband lambda get a little upset when on track and exhaust getting very hot being a bit close to the head. When I moved it 6" further away it was fine.