Are 3 16mm fittings ok for up to 500 hp? One on each side of the block and one rocker cover fitting, - all takes 16 mm internal diameter hose.

 

I wouldn't breath from the rocker cover, your better off breathing from both sides of the block and then having a return to the sump.

 

As above mate no need just use either side of block

 

Your best off breathing form all points then to a catch tank that vents as when oil gets hot and cold it condensates if the oil isent up to temp it carnt burn it off. So letting that vent to atmosphere is much better than leaving it in the engine! Thats why when u look at a catch tank with a sight glass in it it has oilly watery sludge inside if that catch tank wasent there that shit would be in your engine!

 

I have looked at the baily 3 port breather/seperator tank.
The reason i ask about the rocker cover too, is because the ones that only breathes from each side of the block usually use 19mm hoses. But i already have 16 mm pipes on each side of the block and i dont want to change that because i want to avoid the much thicker hoses. So i thought a good alternative to that would be to breathe from the rocker cover too, and then weld an extra pipe in the breather tank.

 

ring spec r they will advise you on a 500 bhp breather, pete has a lot of experince on these power conversions