Thanks for all of the replies to my previous post.
I had asked if anyone had ever heard of an IH 520.
We called a couple of folks who either operated or knew of the tractor. The concensus was that it was a 504, gas, (not 520 - My imagination, I guess) and about a 57 to 59 model. All agreed that this was one excellent machine, and hurt the neighbor's feelings (he had an 841 Ford) on a regular basis with its raw power.
Is there anywhere that I could get a pic of one? Or possibly more info on this specific model?
Thanks again so much,