Factory gages with LS-1 engine, ?

[Tim john---]

Good morning all, I have installed an LS-1 GTO engine into a 69 Firebird. What do I need to do to get oil pressure and temperature to read properly on my original dash gauges (non-idiot lights), these are gages, not light's. I see a flush plug in the one cylinder head water jacket, assuming I can remove and install a NPT to metric bushing and then install an original temperature sending unit, does anyone produce this conversion bushing ? As for oil pressure, I was thinking maybe machine up a "Tee" and install a sender right next to the LS one, get a pressure reading side by side on the same fitting (Tee). Does someone offer this Tee, or another solution to accomplish the same thing. The original LS engine harness has been converted to a stand alone system by Speartech and the computer has been reflashed to run as well, also by Speartech, I am just trying to have my factory gages work too. These two are the last in my list to accomplish in the dash, if you can offer any advice please do so. Thank You very much.

Tim john---