You are on the right track: You need gauge cluster instruments, a new circuit board, and new senders. Sorry, but Pontiac did not install "universal" wiring harnesses. So the gauge package will not function with the OEM wiring harnesses in your car as they came from the factory.
There are two ways to deal with that. One involves modifying the standard gauge dash wiring harness and this is covered in the FAQ's on this site.
2nd method is good if you are doing a total restoration. Just order and install the main and engine wiring harnesses for gauges instead of idiot lights.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
