Brand name...?
In the non supercharged 4-TEC's, you do have some room to use what oil you'd like to use. I only recommend that once you start with an oil, do not change makers since detergents vary from manafacturer to manafacturer.
You can use Castrol, Pennezoil, Vavoline or any other major brand of oil. The only requirement you MUST BE SURE OF is the API designation and weight, which is 10w-40w.
Your 1503, naturally aspirated engine must use oil with an API designation of SL, SJ or SH. These are the only oils you are allowed to run in your engine.
DO NOT use this oil in any of the supercharged models ............:cheers: