*How to hook up mechanical tach w/ modern LS-1 engine ?

[Tim john---]

Good day all, I have a 2004 GTO LS-1 that I am installing in a 69 Firebird. I want to use the original factory gages such as the dash tach, temperature and oil pressure. Are there any special adaptors, fittings, wiring techniques necessary. How can I accomplish this ? Thank You. Tim john---