AV, Good timing. Just finished up my new engine (59AB) and had to fill it. Service manual says 5 quarts. (1952 Motors manual) Added 5 quarts of my favorite Rotella T 15/40 and its dead even with the fill line on my motor. So....it's long enough to reach the oil and say it's full. Cliff Ramsdell
I think the add-a-quart for the filter came with full flow filtration. To my knowledge, partial flow filters such as the flathead used all drain by gravity back to the pan. Thus, there was no quart retained in the filter.
Ok--I measured a dipstick in a '35 Flathead I had and it was about 14" Looks to me like there are several versions of Flathead dipsticks and different length sheath tubes as well. Additionally, from what I see on my vehicles and in this post, some dipsticks are mounted forward of the center exhaust port and some to the rear. I guess, I need to add the proper amount of oil and mark what I have. Thank you all for the thoughts, ideas and laughs. I guess in the end, it has to be long enough to get the job done.
The dip stick on my 1953 Mercury F/H (original engine, rebuilt) measures, from bottom of dip stick to "O" washer at top of dip stick 16". The original spec sheet calls for 4qts of oil w/o filter and 5qts with filter. Seems to work great.