Terry,
I know exactly what you're saying, that's why I said to weight the truck. For example: Chris' post above says his 3500 4x4/5spd weighs 7200 lbs, but my 2500 4x4/6spd weighs 7320 lbs, and mine weighs 640 lbs heavier than his 2500 4x4. So the question is, how much heavier (or is it even heavier at all) is the truck in question? Obviously trucks with different accessories aren't going to match a simiar rig.
There's a formula you can get your trucks horsepower from with a 1/4 mile run, but you need to input the trucks weight to the formula. With such a formula you can estimate how much more power it would take to get a 7500 lb truck to run the same as a 7100 lb truck, and etc.
Yes, the scale operators always leave the displays on even when they're closed,but you'll need a passenger to get out and read the display (it's not facing the truck) while you roll across one axle at a time there in Federeal Way. There's also one on Hwy 410 west of Buckley, and another one on I-90 between Hwy 18 and Sno-Falls exits.
-Mike