Assuming you have a dipstick tube in the block, I'd just make a dipstick out of a piece of rod. Fill the pan with the specified amount of oil and mark the rod with a file, after brazing or welding a washer to keep it just off the pan bottom so it doesn't wear a hole in the pan.

I know if you over fill them they will blow oil out the breather and make a mess. It might be worthwhile to make a windage tray or extend the factory baffle to keep the crank wind from stirring up the oil, though the factory never saw the need so far as I know. Maybe the later 261 pans had such a tray. The pan I have is a 56 according to its yellow color and has the floating oil pickup rather than the fixed one screwed to the main cap.


1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.