Here's why:
* Pan Depth: The dual sump oil pan on a Mustang 5.0 is significantly deeper than the oil pans typically used in the F-series trucks of that era. The extra depth is directly related to the dual sump design needed for high-performance cornering.
* Crossmember Height: The frame and crossmember in a '68-'72 F100 are not designed for the lower profile of a small block Ford that was originally intended for that truck. The existing crossmember will almost certainly interfere with the lower portion of the deeper Mustang pan.
* Engine Mount Location: Even if you could somehow fit the pan, the engine mounts and their placement in relation to the crossmember are likely to be incompatible.
To successfully install a Mustang 5.0 in an older F100, you'll almost certainly need:
* A different oil pan: You'll need a shallower, truck-specific oil pan designed to clear the F100's crossmember. These are available from several aftermarket suppliers. Some even offer a "clearanced" pan to maximize clearance for specific engine swaps.
* Possible Frame Modifications: You might need to modify or notch the frame or crossmember to accommodate the engine and oil pan. This is a significant undertaking, requiring welding and potentially weakening the frame's integrity if not done properly.
* Custom Motor Mounts: You'll likely need custom motor mounts to properly position the engine and transmission.
In short, while it's *possible* with extensive modification, directly bolting a Mustang 5.0 with its dual sump oil pan into a '68-'72 F100 is highly unlikely. It's a project that would require significant fabrication and mechanical expertise.
