I'm trying to change the timing belt, balance belt, etc, but can't loosen the crankshaft pulley nut. I know it takes a lot of torque to break free, and the dealer says it's a normal right hand thread, but I've tried a 450 ft-lb impact wrench and have doused it with PB Blaster penetrant.

Was I misinformed by the dealer, and this is a left hand thread?
Or do I just need to apply more torque, and/or something else?

 

it's normal RH thread.

You just need a lot of torque to break it free.

Check out my write-up on how-to replace the timing belt and water pump. A link to it is located in the Accord FAQ sticky up top. I list the parts needed and posted pictures on how I set it up to break it free. I've done it this way a few times and it's worked great every time.