[mgarblik]

Take the new oil filter housing and get it as clean as possible first. The little spring, disc and retainer plate are all part of the oil filter bypass system. If the filter were to get clogged or you were pumping too much oil at any given time for the filter to pass through, the pressure in the housing would push the disc against the spring and allow oil to skip the filter. The parts need to be in there but not a critical calibration. Use the best parts from your two housings. Oil sending unit is 1/8" pipe thread which is tapered. I like liquid pipe sealant with teflon, but tape is fine. Don't overtighten. If you are running stock rally gauges the transducers are notorious for all kinds of incorrect readings and leaks. I would recommend starting with a known good unit or a new one. Use a gasket and don't overtighten the housing to the block. Good luck.

[Blued and Painted]

Yes a leaking sender can/will cause a goofy gauge readings.