This should be a quick question,
Crankcase pressure, how much should there be and where is the vent so I can un block it? I'm sure theres way too much at the moment.

There's a small rubber tube goes from the rocker box to the inlet manifold, if I take off the tube and put my finger on the end of the pipe coming off the rocker box, pressure builds up quickly, and eventually stops the engine?

Is there another vent hidden somewhere? The pressure is bad, as it will run on the oil from this vent tube if you let it once its hot.

If its not the vent where should I look next? new rings? check compression?

Thanks for your help and if any one knows of an online engine drawing that would really help, until I get a book.

Cheers