stress on pmrs

hey guys.....verified that i indeed have pmrs....and was thinking about this......it seems generally accepted that 400 hp is a limit on pmrs......my truck has dp 80 tow 4 in exhaust 35s and i tow heavy at 22,000 gross combined......my question...is this....if you build a pmr motor to 350.....then tow heavy like i do pushing up hills deep into it.....can you under those circumstances...exceep the stress levels of pmrs and fold a motor...ok ok you can ....but is it likley.....it seems to me that with all the weight you would in effect....be putting as much or more stress on them.....as it would building the motor to 400 hp.....am i makeing sense........................................................q2...also i dynowed 275hp but they couldnt tell me the torque anybody know what 250 hp is in torque...david