The R4360 has four rows of seven cylinders, the R2800 on the original Corsair which I assume powered the original version, has two rows of nine, so a slimmer package on the more powerful engine seems likely. The F2G Corsair with the the R4360 is very similar to the F4U at the front, while the V-326 installation looks almost like the Dart on the HS748 and G1 or the several Dart P-51s that appeared briefly around 1970.
Never heard of the V-326, nor, as far as I can see, has Wikipedia!
Good educational thread this...