You'll need to install aftermarket motor mounts to support the engine in the bellhousing area and probably put a tubular rear mount under the TH 350 extension housing, plus modify the center of the crossmember in the bell housing area to clear the torque converter. Don't remove the crossmember entirely, as it also supports the back of the leaf springs and prevents flexing of the frame. A driver's side exhaust manifold for a 55-57 passenger car V8 will clear the steering gear since the outlet flange is near the front of the cylinder head. A 1958 or newer 283 V8 engine will have the side mount bolt holes that will make the engine installation much simpler.
Jerry

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