This photo gallery shows us details of a factory 74' Porsche 911 RSR 3.0 Liter BEHR Front Oil-Cooler.
The BEHR oil-coolers have a built-in "oil-pressure by-pass valve" to protect the cooler core from bursting in case of over-pressure. You can clearly see this by-pass valve in one of the photos.
Dimensions are as follows: H 6" x W 4.5" x L 24"
:: Reproduction 1974 BEHR Front Mounted Oil-Cooler ::