This is the correct oil pressure relief valve used by the Porsche factory in the 914-6 GT race cars https://pbase.com/9146gt/image/22561541.

Starting with this photo and the following two, those show the later 911 RSR style oil pressure relief valve https://pbase.com/9146gt/image/22561542 which is NOT the correct valve to use in a 914-6 GT. Having said that, the RSR oil pressure relief valve works performing the intended function, but it clearly stands-out as incorrect to those who know better.