Thanks Max,

Thanks for the informative reply, I am sure that will help a lot of people sort out this kind of problem. As you say little things add up to make one big problem!

I do have a breather in the other valve cover and there is the additional engine breather on the 327 as well.

I am buying a new carb tomorrow as I think that must be the root source of
the fuel in the crankcase. Obviously the piston ring blow-by will have to wait, but hopefully I can avoid a repeat of this incident.

Thanks everyone for all of your help, much appreciated, we all learn so much from your input.