Well yeah, sorta similar comparing LS3's stock 230 rwkw to L77's stock 225 rwkw... off the shop floor there's not much in it. After all who's counting a few thousand bucks a year here and there, coz V8. Irony is L77 is the same V8*
Recently in a thread here (where @Tazzl ponders making an AFM denial dongle potentially adding more or eliminating AFM operation) that you can swap a tune into AFM cars that saves 30%-50% in urban and country driving.
Search YouTube for videos demonstrating AFM cars stop/start in suburbia 50-80 kph averaging 7l/100k according to the DIC. Tune and granny driving, yes, but nothing as extravagant as claiming LS3 makes +34 kW over the L77. Seems from above most that energy goes out the exhaust!
I must make a video showing realtime litres per hour vs kph same time as the calc PID, background of various environmental and driving conditions.
Oh this is all jest BTW, there is not much in power or economy one over the other. Also i essentially rebuilt my L77 for power and economy taking a world of driving (actually 7x world circumnavigation) into account. So grain of salt, if you don't give a toot about an extra few grand a year you're welcome to the belief LS3 with shorter gears makes good sense, economically. Probably as much sense as the performance argument at least!
* apart from being a pube breadth (SAE) bigger either side of bore and on the cam lobe.