Thought we had this all straightened out a month ago. The stock 1/8" line is a copper plated steel line with two of these nuts: Edelman #111200, Weatherhead #6100X2 on each end. And the 1/8-mpt to 1/8" tube connector: Edelman #112220, Weatherhead #6200X2 belongs in the block.
The back of the stock gauge should not be a 1/16" Male Tapered Pipe Thread and if you try using a tapered pipe thread you‘re cross threading it. MPT is 1/16”nom. 27tpi and the correct double compression nut is 5/16“-24tpi.
God only knows what a reproduction gauge would have tapped into the back of it, but I would hope they were using the same thing the original one had.
That “kit” from the FLAPS with the 1/16” MPT compression connector fitting is not the correct fitting for these gauges.
Here is the correct stock Oil pressure gauge plumbing:
http://www.pbase.com/dennygraham/image/137095044/large Denny Graham
Sandwich, IL
