Supposedly problem is mainly when pushed hard around corners so a good sump design with a bit more capacity never hurts and the drain back from the back of the head is not difficult to implement even with the head on the block as long as the engine is out.
I have a 4 port euro head, 272 hks cams & would like to rev it to 8500rpm in NA for hillclimbs so should do the above.

It just so happens I have the engine out because I am welding the oil return to the sump from the turbo with -10 fittings. I am very interested in the oil mod to the head if it doesnt have to be removed. What was the process if you dont mind telling me.

Also I am not too worried about the sumps oil capacity as my ute will be more of a daily driver with the odd squirt down the quarter mile.

Ah probably no need then, but if you do the rear of head mod you just need to use putty or blue tac on the inside itll stop all the shavings from drilling and tapping for brass elbows.
Very little needs to be done as the holes are already there just pop off the welsch plugs.

http://www.sxoc.com/vbb/showthread.ph ... tion-prevent-modification

http://images.search.conduit.com/Imag ... PV=FFSBCUID&start=0&pos=1

http://www.driftopia.com/bb/viewtopic.php?f=11&t=87&start=30

reference section very good!
http://driftopia.com/blog/ca18det-info/ca18det-tech/

bottom of page
http://www.sxoc.com/vbb/showthread.ph ... revent-modification/page4

http://www.sxoc.com/vbb/showthread.ph ... revent-modification/page5

http://www.sxoc.com/vbb/showthread.ph ... revent-modification/page6

Wow man thanks heaps for those links, so much info for me to absorb. I am not sure if I will do the mod as I am knida short of space between my head and firewall. I might just leave it and try and find another head and enlarge the factory oil return holes.

Further on it seems those in the know use just 2 separate breather catch cans for each rocker seems to be the ultimate solution as long as they are vented to atmosphere as well.

2 catch cans on each side, may be if I had the room, man there would be hoses and cans going everywhere. Plus I am trying to keep it as legal as possible so I will not vent to atmosphere. I think I might make sure my engine breathers are clean to start with and look at modifying a second head for the future.

Yep after engineering helps but the breather catch cans can have filters on the before venting to atmo like rocker cover breathers.

you sure about that D, i was sure that crank breathers had to be plumbed back into the intake so the engine consumed the crankcase vapours. Even with a filter on the outlet of the catch can vapour will still escape to atmosphere. But hell if I dont need to then I am all for venting to mother nature, makes plumbing a tad easier.

Pretty sure all crank case vapours are to be drawn in through the intake. Most stock set ups have a hose drawing the vapour from the block into the intake manifold and a fresh air inlet somewhere on the block so air is drawn from a filter through the block into the intake. Clearly this won't happen under boost so you'd need a non- return valve in the inlet hose.

Check out the emissions control section, there's some good pictures in there that show how a PCV system works. I can't imagine a competant engineer letting something like that slide. Most traffic cops can pick up how a PCV is supposed to work. Also take a look at any stock car. Since about 1970 they all have one.