Got our 71 Cuda running for the first time and I find that the stock ralley oil and water guage are very slow and don't seem real acurate.

It take awhile for the oil pressure to come up off the bottom after starting and only comes up about 1/3 the way on the guage. Water is the same way, hot engine turn the key on and it take along time to come up.

Fuel guage seems good and accurate.

Amp meter will bounce around some times at idle and show high charge when you come off idle. Next time it reads just fine, slighley up on the chage side. Have checked and alt and regulator are working correctly.

Also the tach is way off, was thinking of getting this for it http://rt-eng.com/rte/index.php/67-74_Tach_Board_with_Calibrator_Built_In

Any ideas or suggestions???

The factory gauges in good working order are slow. My totally restored Rally cluster with new senders is slow. At startup I ran a simple mechanical OP gauge and pressure came up quickly (less than $20 at a parts store). If you are concerned, the simple gauge is a diagnostic.