The blocks are the same.
The crank is the exact same in both engines
The cam is interchangeable but the WF has more lift . 308"
The Animal cam is .257"
The lifters have a larger diameter in the WF
The WF has a Briggs Billet rod.
The pistons of the WF have some what of a dome on top.
The heads are interchangeable.
The valves are the same dimensions except for the keeper grooves
You must use WF springs and retainers on a WF valve.
You must use Animal springs and retainers on an Animal
The push rods are interchangeable.
However, you can use aftermarket springs and retainers on either valve if you choose the correct ones.
The WF intake manifold will not work on an Animal and visa versa. The mounting holes are in different locations.
The WF uses and 26mm PZ carb and the Animal uses a 22mm PZ carb
The air filters are not interchangeable.
The WF uses the same flywheel as an Animal but the WF ignition coil has a 7100 Rev limiter.