Oil level in Model F

[gary ca]

I have a Model F that that the previous owner rebuilt the engine. When it runs, number 1 cylinder fouls the plug with oil immediately. Also it pushes oil out the head gasket near the same cylinder. I have inserted a scope inside and can see oil on top of the piston. if the picture posts, you can see the oil around 10:30.

Could be an incorrect or broken oil ring. before I tear into the engine, I want to make sure that it is not something simple, like too much oil. The manual says 12 quarts. I drained 11 out of it. The model F does not have a dip stick but a float in the pan that has a measuring rod that is visible. See pic if it posted. I have a second Model F that has slightly more than an inch of travel on the float. The problem F, with 10 quarts, has 2 inches of travel. I am not sure how both floats are constructed so it probably is not a good comparison. This weekend, I plan on draining and measuring the oil in the second F. I am just wondering if there was a change in the oil pan designs in later models. Both of these Fs have serial numbers around 2500. Thanks for your help.