I looked at two different IH 574's with loaders. Price on each was $8500 and $7700, it sounds like that league of tractor is what you're looking for. The higher priced unit was at a very high priced used tractor dealer (Pomeroy) and the other was at a implement dealer in Nevada, Iowa.
The 460 I bought is 1959 and it has 48 hp. But I think I'd be hard pressed to get that out it today for 2 days in a row. Something would probably let loose.