I guess that's where hot-rodders and racers differ. I wouldn't build an "improved performance" engine with such a big compromise built into it just for the purpose of aesthetics. Especially when there is a better factory alternative available.

anyway, I had an hour to spare and just finished typing this up...

OK, here goes. First some basics that we can probably all agree on. although I'm sure some of them will be contentious...
1) The amount of power an engine can produce is largely determined by how much air/fuel it can pump.
2) The main factors (variables) in pumping air and out of a given engine is the movement of the piston, and the timing of the valve events.
3) The dynamics of how the piston moves is determined by the crank's stroke (or more correctly the crank pin radius) and the rod length.
4) during the course of the 4 stroke cycle, the piston will come to a complete stop 4 times.
5) the remainder of the time the piston is accellerating. (decelleration simply being -ve accelleration)
6) the dynamics of how the piston accellerates is determined by the crank pin radius and rod length. (Yes, I know I'm repeating myself)
7) piston speed (well, probably more correctly the instantaneous accelleration of the piston) at and around the valve events is largely responsible for determining the dynamics of the intake and exhaust gasses.

and some more complicated facts that are really hard to get your head around...
8) If the piston travels the full length of the crank's stroke in exactly 180 crankshaft degrees, it stands to reason that at exactly 90 crankshaft degrees the piston will have travelled exactly half its stroke in the bore, yes? Well it doesn't. I bet you don't believe me. every mechanic I ever told this did not believe me either. Unfortunately my memory, not to mention my maths skills are not up to the job of explaining this, but it is true nonetheless.
9) the piston will always move more than half the crank's stroke in the first 90degrees of crank rotation. How much further is determined by the relationship of the rod length to the crank pin radius (which is consistent with rod to stroke ratio).
10) therefore, the piston is moving faster in the first half of the crank rotation, than the sencond half.
11) max piston speed occurs when the angle of the rod is tangetial to the motion of the crank pin. The shorter the rod you use, the earlier (in crank degrees) this happens.
12) now all of that was to get us to this point -> This has a few real world implications (that I can remember); reduced max operating speed because the safe peak piston velocity will be reached earlier, and reduced mechanical efficiency because the piston has less time to exert force to the crank around the optimal angles, and thirdly because piston speeds at times of the most important valve events are higher, the engine is less sensitive to valve timing.

That is why "I reckon" that volumetric efficiency will be comprimised with the short rod A14 crank combo you're running. Maybe you can see now why I didn't bother to explain all that in my first post, and just said "I reckon"... which is why I suggested you read up on it for yourself. The details get sketchy with time, and my explanation is definitely lacking in clarity and vital chnks of info, but I'm pretty sure I have the facts straight.

While I can't remember all the details, I do remember that the dynamics of the piston at times of critical valve events are more favourable to performance engines with longer rods for a given stroke. Obviously only within a certain range, but I seem to recall that many many years ago race engine builders aimed at 2:1 rod to stroke ratios, but I think a figure around 1.8 is more flexible and realistic. Rod lengths under 1.6 were though of as poor according to my memory. And your rod to stroke ratio comes out to about 1.57:1, but I used less than 100% accurate rod length figures in that calculation, but it shouldn't affect the results to the quoted accuracy.