Mopar Performance Purple Mechanical Camshaft - P4120653AE Cam Card

What rear gear? was it 3.55s?
what weight again? Was it 3000 with you in it?
what size tires?
For the short answer, scroll to the bottom,lol.

Given a 3.315 stroke and 9.61Scr, with a 3000stall, even a lock-up; the fuel mileage will be lousy with even a modest cam. In which case, you can bias the combo towards performance, and drive the 2liter grocery-getter for mileage.
However, I don't think it would be prudent to recommend an LSA until you have decided more about the cam, ................ because, as we have seen, the pressure moves around an awful big bunch.
And pressure is power.
While the 3000TC is forgiving of less pressure, I still don't think that's a good reason to abandon it, because that same pressure works from stall to shift-rpm in a similar but different way.
That 3000 stall comes in a tricky place. Your ignition timing is often or can often be, a challenge to engineer, between 2500 and 3500.
In Second gear, at zero-slip that is from 38 to 54 mph, with 3.55s and 27" tires. So that is a big window, and you will spend a lotta time in there with a streeter. So, that kindof points to being careful with the pressure in there, or being conservative on the timing in that zone. A lot of guys will crank the timing in early, often 36/38 degrees with iron heads, and in as early as 2500. IMO, that is usually a mistake, but they get away with it because most guys don't push the pressure limit, and will slam a hi-stall into it. Plus with a short-stroke 340, you can get away with more chit, that you cannot, with a longer stroke.
Furthermore, your cooling system will play a huge roll in all of this. IMO, you cannot tune an engine running on the edge, if you cannot control the temperature precisely. So like with an electric system cycling on/off between two set points often 10 to 20 degrees apart, you are just asking for trouble. Don't even go try to tune that. Your operating temp, needs to be rock solidly controlled to a very small window.
I chose a set point the gets me 205 to 207 degrees at a particular reference point on the intake, just below the Stathouse, as measured by an IR gun. Additionally, my carb runs on air that it get from atop the hood. And that atmospheric air runs between 60 and 90 at most so, again, a small window, as compared to say 60 and 200 with underhood air. So the bottom line is I get a happy engine, that I can build a curve for, that most guys or at least a lotta guys can only dream of. And so, I get performance numbers that some guys on FABO I'm pretty sure they find them questionable at the least. One guy said my results were impossible. One guy didn't flat-out call me a liar but I bet he was thinking it...
Anyway the point is that pressure and heat are power. But when you desire to push the limit on the street,with iron heads, it often leads to a combo, that has to be re-engineered due to problems with detonation. Which sorta sucks.
It has been said many many times, by way smarter guys than me, that you will lose more power by not being able to run full timing, than by simply dialing back the pressure.
Besides, you are building more of a cruiser; am I right? Allbeit with some hi-flow heads. So by putting the power in the heads where it belongs, You can sacrifice a bit of, both, pressure and rpm; to get some driveability.
With 3.55s you have already pushed your operating roadspeed up some, IMO a lil high for this combo. Earlier, you were thinking of a 224 cam , but the switch to a solid on a tighter LSA, will allow an easy 230* for the same pressures. So, a 230 cam will peak around 5200 in a 340, and depending on the LSA will allow a shift-rpm of about 200 to 500 rpm later. The 108 will drop off pretty fast, so lets call it 200 and therefore an optimum shift rpm of 5400. With 3.55s, and 10% slip at WOT, this 5200rpm powerpeak occurs at 43mph in First, and 73 in Second. The 1-2 shift split with a standard TF is 59% so shifting at 5400, the Rs will fall to 3200, and your 3000TC is just right for street. But it's still a long climb from 43mph to 73 some of it in a low-power zone created by the 108LSA.
See, the 108 creates more power, but it does it with rpm, and sacrifices a lil on the way there. So with a power peak at 5200, you can expect a torque peak at around 3700, which in Second gear is 52 mph. So from 43 to 52, the 108 cam is struggling a tad. When it gets into the meat of the curve, it will blast thru there, and you'll really feel it. Not like a 114 which is more like a tractor.
There is a very good reason why most modern cams are supplied on 110s, they just work and are very street-friendly. You can throw almost any timing curve on them, and just drive them. But every guy in town has one so when you line up, you got no surprises for the other guy.
So, while the 108 does have the potential to make more absolute power,
the question is, on the street will it be better than the more typical 110s? Because of the "speed limit" and just the two gears to 80 mph, I don't think you will see it in the ET. First gear you will just burn thru. So the race starts in Second at 43=3200 and ends at 65=4330, almost 900 rpm from the powerpeak, and perhaps 600 after the torque peak. I think you could be quicker with less LSA, and quicker with a smaller cam spooled up with say 3.91s or 4.10s.. For example, 3.91s would get you 65=5100@10% slip. This would allow a power peak of say 4800 with a 110LSA cam. And that looks like it could be a [email protected] cam. The absolute power would be lower, but the average power between 43 and 65mph could be nearly as much, and the ET could be very similar. For a streeter, more is not always better.

With your lightweight car and 3000TC, I would want to give the 108 a try, for sure, but it sorta depends on the rest of the cam, and the combo.

One thing I forgot to mention; the 108 cam, in these sizes, has lots of power-extraction, to boost your mpgs. All you gotta do is run the Cruise rpm high enough to keep the engine out of reversion, which with a 230/110 cam is about 2200; so you got that covered with the 3.55s; 2200 is about 52mph, so you might consider that your minimum Cruising speed, lol.