I don't think its too much overlap, but you are right, at some point narrow LSA and duration puts overlap at a point that at low rpm things are pretty "wet" at the sensor and you can do some things to make it a bit less fussy.  These aren't in order, I typed as I thought up things that I did to tune my SEFI more to a point that it's pretty much new car like now

Look at FAST's directions or call them to see what they say, but one thing to consider is O2 sensor placement.  With normal long tube headers, usually the cleanest place for the O2 sensor is the collector or the reducer.  However, this can be too far back and at low RPM or idle the data from the O2 sensor is slightly delayed and does correlate to the specific event that the computer THINKS its talking about

It's more of an issue on SEFI installs, but its always better to put in in the right place as software assumes a certain time between a cylinder firing and how it affects the O2 sensor.  If you put it farther back, unless you have a way to adjust for the lag, idle and low rpm can suffer (a little, this isn't critical "wont run kind of stuff, it really depends on exhaust flow, pipe size, etc)

The Powerjection, EEC-IV, and a GM based hodgepodge I did a long time ago, all liked the O2 sensor less than 18 inches away from the exhaust port (more or less), with some narrow band installs recommending as close as 9 inches from the exhaust valve.  That usually puts it in a primary tube though, so in the end, just try to get it where the manufacturer wants it, or as far forward as possible.

I actually put mine way back, opposite of what I am telly you here, but in the EEC-IV setup I use, I can manage O2 sensor delay and bias.  It still would be better farther forward, but the software gets it 99% there

Another thing to do is really take time to understand how an idle air control valve works on your system, then adjust correctly.  They are all a little different, but when adjusted right, the computer doesn't need to make drastic changes at lat idle or transition.  There are two things to think about, mechanical adjustment of throttle plates and ECM control of the IAC valve.  When you do it right, the IAC will adjust whatever you need it to, if you muscle through and force it to try do more, or ask it to do less than its supposed to, idle will suffer

Finally, if you have the ability to adjust your injector timing, I can help you with a table that will tell you the best time to fire the injector based on your camshaft events, desired duty cycle, target a/f mixture and a few other inputs that I can't remember, let me know. 

I did adjust mine significantly.  However, note that it doesn't do much above about 2500 rpm as the injectors tend to be semi-continuous and sort of "fog" the plenum, it does however make a difference at low end and idle, essentially making sure the injector doesn't fire during the higher lift overlap periods.  Once you get off idle, you could switch injector wires around and not even notice it, even in a SEFI system, but at idle and low rpm, it can make a big difference

Got it

Just keep in mind that a quicker mechanical advance curve has more advance at every RPM.

If all in at 2200 pinged but 3000 doesn't, I'd split the difference with one light and one stock spring and see, the motor should like the additional advance, and that alone may help cruise mpg a little

I basically built a simple linear chart with 14 initial, then all in by 2500 versus what you have now.  As you can see, it does add quite a bit of timing at your cruise rpm, might be worth exploring the mechanical curve a bit more (although of course I still think I'd consider advancing the cam for drivability)

I have a little bit different experience.

First, Barry and Jay answered your question correctly on shifting the curve down, but I don't think it was necessarily the right question for cruise mileage.  If you dyno'd a 109 ICL cam then dialed it in to 109, my guess is the entire curve would be very similar with a little nod to the 109 for the peaks.  So the WOT curve under power wont move much

However, would you notice part throttle response going from 109 to 106? 

I think it would be very noticeable, for example, I took my 427 from 108 to 105 and it was dramatically better part throttle and gained 3 in of vacuum at idle and it was far happier in 4th gear (back when it was a single plane 427/4 speed/3.70 with a 300 adv/250@.050 108 LSA cam)

In addition, in 2001 I had a 2000 Dodge Ram EFI 360 that felt flat to me, after realizing they retarded the cam for emissions, I took it from stock 110 ICL to 106 and it picked up noticeable response down low and idled much cleaner.

In both cases, I based it off intake closing point, but even in the late 80's I used to advance stock SBC cams in trucks because they were so much happier at 4 degrees advanced.  I didn't know why back then, but they did real well and after initial experimentation I kept doing it.  Old school experimentation basically after hearing the old guys used to retard them for RPM.

However will you get get better gas mileage?  My guess is that having the cam advanced and some careful tuning, the engine would be more efficient part throttle and therefore it would get better mileage.  How much?  Probably not a huge gain, but my guess, and almost a promise, is that you'd like the way it ran.

Last spring I dyno'd a 44 inch Rat motor Chevy. in a 67 Chevelle  After tuning it was about 480 to the wheels, needless to say it wasn't a shaker, but the flow top lid with a 14 x 3 K&N filter gained 5 hp or so over the same filter with a chrome lid with no significant changes to the a/f ratio.

I had also heard they didn't work by some pretty big names, but this one did OK

Jay, awesome motor and glad to see the results from intake port length changes.

Not sure how easy it would be to measure on the motor, but could you do some before and after calcs based on the old Ramcharger's wave tuning math?

L = 80500 / N            
            
L = duct length (inches) from Plenum ( the first reflection point) to the back of the intake valve.            
N = Engine RPM for maximum tuning effect

Solve for N before and after and see which one was closer to where you made power?  Needless to say the shorter stacks did well so it should be closer, but it would be interesting to see what the numbers came out to be.  For an IR manifold L should be from the valve to the end of the stack      

      

I personally wouldn't run any more than a 294S with only 418 cid and 10:1, and even that is a bit less compression than I'd like to see.  FWIW I run just a bit less cam with 10.7:1 compression and it'll run on anything.

You can even go less cam than that, but as you noted,  I don't think you'd get the top end charge you'll want to see.

Not Jay but a SFT can be absolutely reliable.

I ran a 300 adv/ 250 @ .050 Isky in my 427 for years and the current Erson has been in since 2006, driven everywhere

Even with standard lifters, make sure nothing hits, run good oil, and keep idle up high enough to throw some oil to the lobes.  All those things should be even easier with the Schubeks

As far as 294 vs 306, I ran a 306 in a 462 Rat Chevy and although it made a ton of power up top, I think it was a little too much cam for the street.  The FE isnt a direct comparison to a big headed Rat, but unless you are running a bunch of compression, I'd lean toward the 294

A quick WAG - The 306 would probably need 11.7:1 compression or more, the 294 would be happy around 11:1

Good stuff Jay

First, let me ask you to break the calculator back out, as an MBA and Strategic Intelligence grad, I'll have to lean on you to tell me how to mathematically get to the answer to my question

So, if you look at what you calculated, could you back it into a "resistance to change" calculation?

What I am trying to say is if you had a an engine at 450 ft lb at a steady 2000 RPM with one flywheel, is there enough information to calculate how much difference in torque the motor would have to provide to keep one or the other flywheel at 2000 rpm with an increase in load? 

I assume there would be time and load variables in there too, because once the inertia is "eaten up" the motor would have to work harder to keep the wheel spinning.

Thanks