How do I find the serial number and other important information of an old airplane I have?
There are three pieces of paper the FAA issues which would fall under the concept of "title" to an aircraft.

The first is an aircraft lien (typically held by a bank when you take out a loan collateralized by the aircraft). This is probably not what you're looking for, but you should inquire as to whether any liens are held against the aircraft before doing any work, just to be sure you have "clear title" to the results of your work.

The second is an Aircraft Registration Certificate - this is a record tying the N number (in your case N97554) to the aircraft itself.
In your case the registration is Revoked, so once reassembled the aircraft would need to be re-registered to be flown. This would be a "Call your local FSDO" situation - Presumably the registration was revoked when the aircraft registry changed to a 3-year expiring registration period.  Also as there are multiple owners listed on the registration re-registering may require more work.

The final piece of paper you need is an Airworthiness Certificate - this should be in the aircraft, and is valid forever. If it's not in the plane you can get a replacement - again, contact your local FSDO.

If you need information you don't have, or want to confirm it before talking to the FAA, look for the aircraft data plate. On Stinson aircraft (going by the N number you provided) the data plate is usually located on the firewall above the copilot rudder pedals as shown here.
On newer metal aircraft it is often located on the tail, under the horizontal stabilizer.

For more information on the aircraft itself check out stinsonflyer.com.