Converter and gear swap.
With 28" tires and 4.10 gears I run about 3100 rpm at 60 mph with an 8" 5500 converter. What size converter and stall speed is PTC looking to do for you? I'd imagine that you'd be at least couple hundred rpm higher than what I'm running if you're using 4.56's (assuming you'll have a high stall converter).