I'd keep looking unless that particular truck has everything else you want on it & is a deal. A freind of mine just bought a loaded '08 F450 Powerstroke with 4:88 gears & 28,000 miles on it for 32k out the door & all it needed was a ding in one rear fender repaired. He says it out pulls his previous '06 F350 even though it had an edge programer & 4:30 gears. He's pulling a 14,000 lb trailer so driving 65 due to the 4:88s doesn't bother him. He said as far as RPMs there isn't as large a difference as you would think since the F450 comes with 19.5 wheels & I think 32'' - 33'' tall tires. When he was looking he said the F450s were consistantly cheaper than the F350s for some reason - maybe time to step way up with your new rig.
