It's really quite simple.
With a given pair of lobes;
When you decrease the LSA, you are moving the lobes together, so the first thing you will notice is that the overlap increases.
Simultaneously the durations of compression plus extraction also increase.
Going from 114LSa to 108 is 6*.
Overlap increases double of that so 12*.
Compression Plus extraction also increases 12*. Now; you can split these extra degrees between the two, almost any way you want to.
What you end up with is;
1) because of the earlier-closing intake valve, the low-rpm cylinder pressure rises, resulting in more low-rpm torque.
2) because the extraction degrees have been increased, this allows more time to transfer force from the piston tops to the crank to the flywheel, and theoretically she should get more torque, and better fuel mileage
3) the increased overlap, increases absolute power over the nose, at a slightly lower rpm, with a more rapid fall-off after the peak, but steals some fuel economy especially at lower rpms.
4) All in all, with the tighter LSA, you get a torquey engine with a narrow powerband, suitable for the Regular A833, and better able to put up with hiway gears.
Lets look at the Mopar 268/276/114 cam.
In at split overlap, the numbers are;
268intake/276exhaust/114LSA/ Ica of 66*/and
44* overlap, 114compression/106extraction
Ok lets tighten those same lobes up to 108, and I get;
268intake/276exhaust/108LSA/ Ica of 60*/and
56* overlap, 120Compression/112extraction
Here you can see the 6+6 degrees on each side of the lobes, yielding 12* more overlap, and plus 6* each to compression and extraction.
Now; 114* of extraction is quite a lot; excessive perhaps for a city car. IMO 108 would be lots, so then, you could trade 4* of extraction away, to compression, by retiming the cam.
But 120Compression +4more=124* which may be excessive for a high-compression engine, possibly putting it into detonation.
As to the overlap, this only works with headers and a free-flowing exhaust. An increase of 12* is a lot! about the same as 1.5 cam sizes in the 110LSA group, so you can expect to really feel the surge.
So, then, again; it's all in the combo.
If yur stuck with an automatic, the 108 cam has a fairly narrow power band, not at all suited to the WIDE 1-2 shift of the TF trans,(1.45/2.45= .592)
but better suited to that of the A833;(1.92/2.66=.722).
Some of that, to all of that, mismatch, can be side-stepped with a higher stall.
Ok so if you don't know about powerband requirement;
If you have a cam that wants to be shifted at 5500 rpm. And you are using a TF trans, then, when you out-shift First at 5500, the rpm will fall to 5500 x .592= 3256, therefore your powerband requirement is from 3256 to 5500=2244rpm. So your engine for this combo, needs some grunt at that 3256 to pull up the average-power from there to shift-rpm.
Whereas;
If you have an A833, the 1-2 rpm drop is to 5500 x .722=3971, therefore a powerband requirement of from 3971 to 5500=1529 which is just 68% of what the auto needs.
To be able to use the 108cam, in a competitive fashion to the 114cam , in the auto-combo, your auto would need a higher stall, to put the rpm to a similar 3971 rpm.
This is the simple solution, not the only solution.
As to single versus dual;
The dual pattern allows you to move the installed centerline away from split overlap without affecting the usefulness of the overlap very much, AND in street sizes, increases extraction for more torque and better fuel economy
Lets revisit that 340 cam but put the intake lobe on the exhaust side as well; I get
268/268/114LSA/Ica of 64* in at +4 (4* advanced), and
40* overlap/116Compression/108extraction.
Compare this to;
44* overlap, 114compression/106extraction from above
With the single-pattern, we gained 2* each compression and extraction, but lost 4* of overlap, and furthermore, overlap is now split 24/16 instead of on split overlap of 20/20.
Lets tighten it up to 108;
268/268/108LSA/Ica of 56* Advanced 6*, and
52* of overlap/124*compression/ 112 extraction.
As you can see, the numbers are a lil messed up.
However; the 124* of compression could really help a low-compression engine. and
the 112* of extraction is guaranteed to help with making torque. and hi-way fuel-economy, even around-town economy. but
overlap is now split 32/20 instead of 26/26, which is a bizarre bias towards the intake side.
So IDK. IMO at this cam-size, I don't see any advantage of an SP cam.