I searched and did not see already posted-
2013 "G37" to get 5.5L V8 AMG. Assume Z would follow same in 2014 like 08 G/ 09 Z
2013 Infiniti G Coupe - 2013 Infiniti G Coupe Future Car First Look on RoadandTrack.com
In other markets, including the U.S., it will be available with the M Hybrid’s gas-electric system and AMG’s 5.5-liter V-8 that will produce upward of 360 bhp. The latter will most likely wear the IPL (Infiniti Perform*ance Line) badge and go after BMW 6 Series and Maserati GranTurismo customers. While the base G sedan is expected to come with a mid-$30,000 price tag, you can expect the hybrid version to be priced near $55,000 and the V-8-powered Coupe to cost around $70,000. There is the slight possibility that Infiniti will decide to build a coupe version of the M sedan, and place the V-8 (or even a more powerful engine, perhaps the 6.2-liter AMG V-8) under its hood.