If it's like my 220D, the mark for the camshaft is on the drivers side of the front cam bearing tower. It is just the tiniest of a bump, almost looks like casting flash! Supposed to line up with a notch in the cam gear washer.
Don't know about the IP...

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1971 220D/4-speed ~250K mi. Family owned (dads side) through three generations since <5K miles.
1992 Chrysler LeBaron, 3.0V6 125K. Family owned (moms side) through three generations since new.
1977 Chevy Camaro Continual hotrod project
1970 Cadillac Sedan DeVille 472ci and nearly 19' long
1974 Fiat Spider Still needs work