How do you know it's an IH crawler? Doesn't look like it to me. I don't know of any IH crawler that has a front grill with with that vertical arc and bottom that is more forward then the top.
I know that neither the 500 or any of the TD crawlers have a grille like that.
That front grille is pretty unique and distinctive. I don't know what it is, but can see what it isn't. I don't know of any IH or Oliver/Cletrac that has grille like that. In fact, not many crawlers or wheel tractors that have a grille more forward at the bottom then the top and curved. A few are close like some Cockshuts, Huber,Graham-bradley, Co-op, Friday, Oliver-Cletrac Hg,Oliver 60/70, Monarch,Love, Allis Chalmers 50 crawler, . . .