I have some engineering questions for my technically-minded watchers, since I can't find any credible online sources to answer them for me; I might even post this in the Forums someday:

"Given two hypothetical automobile engines of 'equal everything', one a V8 and the other a V6, what would be the difference in efficiency and in output?"

Assume the only obvious difference is that the V8 has two extra cylinders/pistons and shorter piston rods, necessarily; also, let's say the V8 has a 1:1 bore/stroke ratio, for the sake of simplicity & standardization.

"Equal everything" applies to all of the following:

1)   total displacement [example: both are 4.0-liter (hypothetical) engines].
2)   mechanical measurements/designs: cylinder bores; piston heads/rings; valves; spark-plugs; camshaft/crankshaft [notwithstanding necessary adjustments for two extra cylinders/pistons]; cooling-system; battery; transmission; drive-train.
3)   aggregate stroke [the total distance the pistons travel / total length of piston rods].
4)   air/fuel ratio [naturally aspirated] & compression ratio.
5)   engine weight [the iron-blocks weight the same (theoretically), only the shape differs: the V6 is shorter & deeper / the V8 is longer & shallower].
6)   vehicle weight [adjusting for any necessary balancing/suspension modifications per variable tasks].
7)   total fuel consumption [example: limited to one gallon per task and/or per hour].

My own Assumptions/Conclusions (drawn from the above equalities):

A)   Due to energy-conservation laws, since the only fuel (energy) source [gasoline & oxygen from the air, naturally induced] for both engines is the same, the total output (work) – and efficiency – should be the same upon task completion / fuel depletion [examples of various tasks: total laps traveled around a racetrack on one gallon of fuel and/or one hour; short-track drag-racing to reach finish-line first; top speed achieved on long, level track; hauling equally-heavy cargo/passengers on various terrain/traffic conditions].
B)   The V8 should be "smoother", due to more power-strokes per crankshaft revolution.
C)   The V8 should be capable of higher RPM's, thus producing more high-end/high-speed torque [due to the shorter stroke].
D)   The V6 should have more low-end/slow-speed torque, due to longer piston rods [more leverage on the crankshaft].

Additional Questions/Musings of mine:

1)  Would the maximum horsepower (foot-pounds) be the same for both engines [at their respective highest point]?
2)  Would the maximum torque (pound-feet) be the same for both engines [at their respective highest point]?
3)  Would their top speed be the same [allowing for a sufficiently long track for each to achieve its potential]?
4)  Are my assumptions on efficiency [equal terminal performance per equal fuel consumption] correct; if not, why?
5)  Are my assumptions in B, C, & D above, correct; if not, why?
6)  Would the friction/heat be equal, since the aggregate stroke and the total energy consumed / exhaust produced are equal?
7)  What would be the difference if the V6, instead of the V8, was designed with the 1:1 bore/stroke ratio [or some theoretically ideal performance-enhancing ratio]?