MG Car Repair: pcv system, crankcase pressure, outlet tube

Question
I own a 79MG Midget that I have put a Webber downdraft carb on and I was wanting to put a pcv system in. I was going to run it from the outlet tube on the rocker cover to the intake. Someone told me the valves were numbered could you tell me which valve to use and do I need to do any thing else.
Thanks
Doug

Answer
Hi Doug,
I could not even guess at what PCV valve to use as that is dependent on the amount of crankcase pressure and volume your engine is producing. The few times I installed a PCV valve in a aftermarket manifold I used the old style MG valve used on the early 60s Midget and MGB. The rest I just welded a port into the back of the air filter can and routed the valve cover hose to it. There may be an appropriate PCV valve from some other car but I have no way of determining what that is.
Howard