What would cause oil to collect inside my intake?

Last night I took apart the intake system of my recently purchased 1987 300SDL because the car was putting out alot of blue smoke. iassumed it was oil consumtion but noticed a pool of oilin the gasket area of the mixing pipe. sureenough there was ALOT of oil an sludge in the crossover and intake itself.

what wouldcause this. i've been told it could bebecause ofan airconstriction/restriction. if so, what could causean air restriction.

anyone haveexperience with this?

 

i just bought it last month. it shows 165,000 but seems to run like it has many more miles on it. i'll never know.

any idea what would cause this build up? it also seems to "miss" some and puts out a blue smoke until it's warm and knocks ALOT.