What Jerry is describing is exactly what I have on my '37. The valve cover has no fill cap. You add oil via the road draft tube, and no, you don't get oil leakage.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix