I couldn't find your block casting but the head is listed as used in a 1946 Fleetmaster. That would mean that your engine has the flat top pistons. In Canada, Chevrolet used the dome pistons up until the end of 1942.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!