I have a 6556 Stock Car from my dads collection of Lionel as a kid - non of his sets included this car. He has no recolection as to where he got it since he was 7 years old at the time. I wish I had the box for it! Thanks for your help in advance!
That would be the 2513W set from 1958. The outfit was headed by a 2329 Virginian Rectifier. The 6556 also was listed for separate sale. Either way, it’s considered relatively rare.