LSA Question

@Dan the man
Here are some theoretical cams, to show you what happens to LSA/etcetera, whilst adjusting the overlap period.
this is just an exercise.
all are in at split overlap.
I set the Ica to 62* for a compression period of 118, which is typical street
I set the intake/exhaust split to 4* for a power extraction of 114* .
I set the overlap to be 20* on the first example and increasing by 8* in each successive one.
Watch what happens to the LSA, and intake/exhaust durations

1) 252 intake/118 comp/114 power/256 exhaust/20 overlap/LSA of 116
2) 256 intake/118 comp/114 power/260 exhaust/28 overlap/LSA of 115
3) 260 intake/118 comp/114 power/264 exhaust/36 overlap/LSA of 113
4) 264 intake/118 comp/114 power/268 exhaust/44 overlap/LSA of 111
5) 268 intake/118 comp/114 power/272 exhaust/52 overlap/LSA of 109
6) 272 intake/118 comp/114 power/276 exhaust/60 overlap/LSA of 107
All of these cams can be installed into the very same short block,
and because the ICA has NOT changed; you can expect
very similar cranking cylinder pressure, bottom-end power, throttle response, and among any three or even four cams in series, even similar steady-state fuel economy. Furthermore the stinking pushrod length can be set just the first time.
Thus , for street
you can build a zero-deck 318 with closed chambers and set the Q with the Quench-pad/gasket and adjust the compression with a step-D cup ,
then have at it.
Hey, it wasn't my idea to start with a 318 ............... lol
OR
still for street;
you can start with a 360, in the which the deck height might fall together at .012 down, slap on a gasket of .028 which takes care of the Q using a closed chamber head, and just choose what ever head has the right sized chamber, no decking required, no piston work, Easy peasy.... 1-2-3
And finally, if the cam you have chosen doesn't work out, just slide another one in with the same Ica except a different overlap; smooooooth.

Just for reference and not specifically related to the above, as to the idle sound;
20* overlap idles like a factory 318
30* overlap idles like a factory 360
44* overlap idles like a factory 340, and is barely noticeable
52* is a lil more than barely noticeable
60* is starting to sound like something is going on under the hood
68* is loping, just a nice warm gentle cadence
76* is very noticeable, especially if you run it with retarded idle timing.

Up to 44* requires no special tuning skills
52 and up will depend on your base ignition timing.
68 and up, the engine will want some bypass air, no big deal
I have not tuned for more than 76*
IMO,
None of theses are particularly difficult to tune. You just gotta give the engine what it wants, and not just throw a buncha timing at it. I mean that sorta works with an automatic, which has a higher than stock stall, but that don't mean it's the right thing to do on the street, and especially not in a DD.