I purchased the early model oil pressure sender replace the one on my 3.0 to match my early style gauge only to find out the threaded portion that goes into the fitting are way different. Anyone know of the adapter I will need to make this work.

This is what I found out but havent found a site selling them.

Porsche sells an adapter bushing (PN 901.101.175.01) that permits the 18 mm x 1.5 fitting block thread to be bushed down to a female 10 mm x 1 that will permit the male threads on the old style oil pressure sender to be used.
18 x 24 mm metal sealing ring (PN 900.123.009.20) to go betwewn the bushing and the block and a new 10 x 16 mm metal sealing ring (PN 900.123.004.20) to go between the bushing and the old style oil sender.

Just ordered from dealer - 12 bucks.