The argument for/against the block of plate for the crank case ventilation system .
Some say it should be retained With/without the one-way valve off the separator in order to prevent the build up of air pressure in the crankcase.
If the pressure builds up, it prevents the oil from draining back to the sump. This is something I have experienced, so I'm in the "for" camp.
Raceline are a highly respected UK builder/supplier of Ford engines to the RWD Escort engine update market, and to se7en builders. They say that if the engine is correctly built, the Crankcase vent hole can be blocked off.
The last time I saw a debate, it was on the Westie site http://forum.wscc.co.uk/forum/
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