Oil Leak on an abused Pinto - help

I am running a standard Pinto of unknown history in the family motorkhana car (Locost chassis). This means generally first gear and high rpm. The engine has recently started leaking oil down the inlet side from I think around the cam cover. What's going on? Is blowby and crankcase pressure likely to do this? Any other suggestions?
regards
Michael Jones
regards
Michael Jones