I dont know why but my car didnt like the vent to atmosphere method at all. I bunged the return to metering head and vented the breather to atmos, ran like a bag of shit, this was a brand new engine with all new breather pipes and spec-r breather. I had to run venting back to metering head. Ive recently removed the ic and pipes and theres loads of oil in there, im putting it down to the small spec-r breather not been up to it, ive got a new bailey one to go on when it comes to it. Just cant work out why it hated been vented to atmos so much???