Carter 504S was listed for '41-'48 Olds 238 engine. Photos of the 1950 revision data sheet, below. The float setting is 1/2" from gasket surface to top of the float seam with needle seated. Hopefully the image in the lower right of the first photo has enough resolution to illustrate that. Not sure why the attachment manager flipped them on their sides. If you copy the photos to your desktop, you should be able to zoom in.