why is my airfilter ful of oil ?

This does not 'just come with age' unless the compression rings are totally shot; this is a distinct fault. The oil there can come via faulty PCV; being new does not mean it is working right. It should flow air at moderate vacuum levels and not flow air at no vacuum or very high vacuum. Likely the PVC is not opening in the moderate vacuum ranges, and the only way that the oil vapors can get out is via the open breather that comes into the side of the air cleaner; it'll fill up the cleaner like you see.

Also, the port under the carb to which the PCV hose connects can get clogged with burned oil vapors and needs to be cleaned out; take the large PVC hose off of that port and make sure air flows freely into there. If not, you need to clean/dig it out.

And make sure the PVC is not backwards.......

Otherwise, perhaps you have sticking compression rings in 1 or more cylinders from gumming and varnish and sitting. Try half a container of Rislone or Sea Foam poured slowly down the carb while keeping one hand on the throttle to keep things revved up to 1500-200 rpm. It'll smoke like hell but may help clean a sticking ring and will clean the intake valves. Then put the rest in the crank case and drive around. It probably will not be the issue, but the copious smoke is fun......