i wouldn't be worried about notching the frame for the coil bucket. not only are you plating all that back with good heavy plate, but the engine mount is there to help support it if welded in. only weight fwd of that is the core support.
i like the idea of lowering the bucket and Frenching it into the frame. should articulate better, more clearance to articulate, more options to lift later, and the free option to nail ride height. plus then it's the chassis that's custom, you ever break that axle in half (since they do that) you can just toss another in there.
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