[51woodie]

Tubman beat me to it, but you will get several different opinions on what oil to use. I have a stock "46 flathead 8, an I made the choice to use Shell Rotella T4 15-40 in my engine. I get good oil pressure and it keeps the engine clean. Available in Walmart in 2 1/2 gallon jugs. About C$45.00 in Canada. Left pic is idle, right pic is road speed.