I'm still having some quirky fuel pressure symptoms. Regulator was set to 60psi upon install, and after a number of months the AEM fuel pressure gauge is starting out near 60psi and sometimes going up to 70psi. The regulator adjustment screw was installed in a manner difficult to adjust without unmounting the regulator.

I presume upgrading the lines and fittings, as well as moving the regulator to the engine bay, will resolve the issue? What are the recommendations for fitting & hose sizing? I think I've read that I need to be careful to not lose fuel pressure due to too large of lines, and to have the return lines large enough? The lines below are 1998 OEM unless modded to connect to AN fittings. The style of AN hose I was considering for the upgrade was 2x15ft of Aeroquip FCC0615-06AN?

1998 Z28
- 418 LS3 with only milled OEM LS3 heads
- 1999+ plastic fuel tank with 340LPH pump & hotwire kit (trap door cut when I still had the steel tank)
- Wix 33311 fuel filter on exterior of rear driver seat
- Fuelab 51502 regulator (6AN inlets) with Fuelab 71501 gauge, mounted near OEM location for fuel filter
- AEM 30-0301 plumbed into OEM LS3 fuel rail inlet connected to cabin fuel pressure gauge
- Autometer 2246 plumbed into front of fuel rail, connected to EGR harness forr HPTuners scanner

I have a Fuelab 81801 fuel filter on-hand to replace the Wix also. Some photos here:
https://www.dropbox.com/scl/fo/6b33q...=ncz8zxpv&dl=0

Thanks!