I was inspired to create this model by a brief note on the wikipedia page for the P-40 that suggests a single aircraft was fitted with two Packard built Merlin engines, one over each wheel, sometime in 1942. I've found one historical photo on-line which appears to show a fairly crude mock up outside a hanger, possible at Wright Field.
I've based my model on a 1/48 plastic kit conversion from ww2aircraft.net that offers a more practical interpretation of the concept than the original mock up. I have added inlets on the top of the engine nacelles because they are such a diagnostic feature of the original (Alison engined) P-40s. As the aircraft looks like the Westland Wirlwind I have invented the name 'Twister' for it.
The spherical depression under the model is for mounting it on a 4.5mm BB.