Styled 1949 Allis WF

The neck of the muffler goes through the hole in the hood from the top. There's not enough room for a muffler under the hood. I have seen drawings in manuals with just a short pipe without a muffler. This way you end up inhaling more exhaust than comfort allows.  The noise may be amusing for short running but not pleasant for a whole day's work in the field. My WF mufflers probably average 2 1/2' in height. The hole in the hood is big enough for the right size pipe. On the WD models with the same engine they made the hole in the hood bigger even though the exhaust goes straight up like on the WF's.

Yes from factory had underhood muffler same as WC

The first WF we had was a kerosene model and they never had a muffler under the hood as the exhaust came out of the side of the manifold at about a 45 degree angle with no hole at all in the hood for exhaust. With the one gallon gasoline tank under the hood, less than two feet away, it would have been crazy to have an under the hood muffler. Using the belt pulley to run the thrashing machine the manifold turned red from heat, to collect more heat in a muffler under the hood would make no sense, let alone to evaporate whatever gas that was left in the small tank.