A 5'6" drum mower will be your best option, plenty around, easy to use and maintain, fingers are old hat now and in inexperienced hands can easily be broken......disc mowers are few and far between to suit a 454.
If you haven't bought anything yet, consider putting your money in your hay turner...you only cut grass once a year, but will need to turn it a minimum of daily for at least a week before rowing it up...that's at least seven operations.
You might get a local farmer or vintage enthusiast to mow it....