I would guess that they just threw that out there as an example of the high end of the FJ40 market. I don't know if I've ever seen a Chevy 4.3 in an FJ40, there can't be too many of them out there, so there probably isn't much of a frame of reference for what they'd go for. I expect that the main premium on this particular rig is bragging rights to boast who the PO was. FWIW, Chevy 4.3s are very common as donors of TBI for 2F FI conversions.