New mustang 69 mach 1 390
 

Just picked up a 1969 Mach 1 will the 390 automatic don't know anything about mustangs and my question is it's in decent shape needs a redo motor needs to be started up after 32 years suggestion whether or not to sell it as is or do minor upgrades to make it run or go all the way I'm into it about 10,000 and the car is definitely a Rebuilder hundred percent complete just set for a long time half covered under a tarp half in a lean-to outdoor storage any suggestions would be wonderful thank you

Sounds like a great project car for someone. It all depends on "Do you have the money and time to do it right?". There are much better people on this site to offer you advice on this. Post some pictures and it might help with seeing what you are faced with...

get a marty report .. then get an idea of what it will cost to restore it then get some ideas of what it will be worth when finished ..S code is a good car to fix or turn into an R code clone ..

A Marti report is an excellent idea and still under $50 I believe. If the Marti confirms everything about the car, it would be an excellent candidate for proper restoration if you have the $$$.
My neighbor has a true #2 1970 Mach 1 with a 351. If would sell in the $25,000 - $30,000 range. Just to give you an estimate on value.

Congrats on snagging that thing!
I have my fiancee's son's '69 Mach 1 at my house right now, waiting for him to pick it up and bring it down to his place in North Carolina.
It's a little less complete than yours though:

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A car this old that "looks ok" likely has a lot of hidden issues or half-assed repairs. Somebody parked this car for a reason; find out what it is. REALLY look hard for rust, particularly in the cowl area. That's make or break on these cars for cost effective. The floors and torque boxes can be redone, the quarters, door skins but, if cancer has gotten into the cowl area, you're better off flogging it. S codes aren't super valuable, unless they are 1968s and Steve McQueen drove it so, you have to watch your restoration costs.