Originally Posted by bucktruck
How much 50wt oil is used in the stock air cleaner system?
The stock air cleaner depends on the make, year, and size truck.
Post that info and we can look up the answer in a Shop Manual and/or Owner/Driver Manual.

If it is an oil bath air cleaner (not stock on most small trucks), it should have a fill line marked on the inside bottom of the side wall.

http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0673.html