I use an sandwich plate adapter on my LS2 05 GTO to adapt the remote by pass oil filter I use. The aftermarket adapters usually are available in different port sizes depending if you're running a small diameter line, or a larger diameter line for an application such as an cooler/full flow oil filtera that needs more flow.
Many of the sandwich adapters have a pressure port as well as a return port to keep both lines of a cooler, or filter plumbed to the same adapter. No return needed to return oil back to the oil sump.
Oil coolers are also available with thermostats similar to a coolant thermostats that stop the flow of oil when the cooler isn't needed due to load, or ambient air temperatures.
Glo Shift has a pretty good selection of sandwich adapters for all applications. I just bought one for the 3.1 engine in my 99 GP to adapt a by pass oil filter to it.
Link to Glo Shift.......
https://www.glowshiftdirect.com/oil-...wich-adapters/
Amazon sells Glo Shift adapters with no shipping charges, Glo Shift needs a $50 minimum to waive shipping charges.
Amazon also has thermostat adapters for oil coolers.
https://www.amazon.com/s?k=ls+oil+co...l_12s97ji989_p
