Welcome to our forum. I am certain you will find lots of folks that are very helpful.
Our 1973 Mach 1 did not come to us with a rear wing, just a front spoiler. And, the prior owner had repainted the car and opted to not put on the Mach 1 stripes as he felt the car had a cleaner look without them. Well, after doing some "needed" upgrades we decided to do a deep re$toration. At the time of the restoration I decided to add some more of the "tinsel" that had been available back in the day. Those items included a rear spoiler wing, the side and rear Mach 1 stripes, the "351 RAM AIR" Call-Out characters on the hood scoop inlets, opening up the ram air inlets to bring cool air into the engine compartment, a set of rear window louver slats, and a set of Dzus hood hold downs.
I think the Mach 1 has a much more sinister look to it with all those adornments. Never mind the fact the front spoiler and rear wing will do next to nothing at the kinds of speeds we are restricted to on the public roads. But, they do help it pop.
I am in agreement with the folks that advise you to get a high quality part for your rear wing. I got ours from CJ Pony Parts, and it was a very nice unit - looks good, installed perfectly. And, just so you are aware, it is possible to put the wing on backward. The proper orientation of any air foil is that the thicker part of the foil (wing) is the leading edge, and is thus pointed toward the front of the car. The thinner part of the foil always pointed toward the rear, thus toward the back of the vehicle. Unfortunately, the way the wing tips are designed, it looks like the way the tips are designed is counter-intuitive. You will be getting told by a lot of folks the wing is on backward simply because of how the wing-tips are swept. If you just recite the mantra, "Thick Edge is always forward on an air foil, you will be fine.
Following is a link showing how our or wing is mounted. Below that is another link with a walk-around video of the Mach 1 on its last day of its restoration.
As for the specs on our Mach 1, they are a little unusual. First, we have a 351W, not C, engine in it, which replaced the original 302 2v. The 351W is built for street/strip performance, putting out a modest but lively 360 HP at the crankshaft. The 2.79:1 rear axle ratio gears were replaced with a 3.5:1 ratio TractionLok gear set, and the original C4 auto tranny has been replaced with a four speed AOD. We also added a Classic Air air conditioning system (and love it), an ACP full length center console, a Garmin Drive 51 GPS and wireless backup camera system, a set of LED panels for the taillights and sequential turn signals, a Dakota VHX analog instrument panel, and a dual electric fan cooling system with an aluminum 3 row radiator. It is one fun car to cut around in, and to cruise in.
Finally, if you need shop manuals, or electrical schematics, my Go To site is Forel Publications. Their PDF file prices are very low, and the information is very helpful. In 1973 the electrical schematics and vacuum line schematics were actually really nicely done, whereas in prior years a lot of the info needed was hard to find, or did not exist for "us mortals." Following is their web site for 1973 manuals:
https://www.forelpublishing.com/clickbank/index.html#1973