Your best bet is to get a shop manual for your car and start from there. It should show you the voltage ranges and such that you are looking at. You will need that information before you can continue. You may be able to pull the information by finding out the sensors your car takes and look at the specifications for the sensors but really you need the information that the dealer would be using. If your speedo is cable driven then you will not have speed information available easily. If your car does not monitor the RPM you will have to add a sensor for this depending on if your car runs off a coil that has an RPM output.
You might be better off adding an after market PCM of a modern variety that will allow you to access this stuff easily and still tie into your factory stuff. You may have to add some sensors that you would have had to anyhow and you likely will get better performance if you know how to tune.