when i first ran my truck i didnt even know it had a vent tube. but then i saw a stock 97 that would blow smoke out the oil dipstick tube and the breather tube thats at the bottom of the motor? y so? i see pullers running and they have a ton of smoke out their breather tube. is it normal on a stock truck or is it a sign of excessive blowby?

 

Blowby is normal and may look excessive at times, especially on a cold engine. Pullers have lots of blowby because they run excessive boost compared to a road truck.
As long as you aren't using more than a quart of oil every 5000 miles don't worry about it.

Blowby out the dipstick tube is usually caused by a torn or missing 10¢ o-ring under the dipstick handle.

Easy way to check blowby> http://www.cumminsforum.com/forum/94...ng-blowby.html

 

Yes blowby is normal, the 12 v just dumps it down by the starter where the 24v engines have a catch bottle that fills up pretty quick.