The alloy heads when combined with a tight quench,
will support very high cylinder pressure on pumpgas .
Good luck getting there with flat-tops and a 340 cam.
It will never happen. See Note-1
If you ignore the pressure possibility, the guy in the next lane with an identical set up but pushing 200psi, is gonna teach you the high-pressure lesson.
Making Power is all about the power of expanding gas pressure. All the cams in any catalog cannot make power without compression.
Each bigger cam will just extend the operating range about 200 rpm higher. So all of a sudden, 5 cams later, your power is peaking some 1000 rpm higher, say 5400rpm, but your pressures is some 40/50 psi down from where it should be, and so, your hiway gears are keeping you in that oh-so-modestly-powered zone to say 4000 rpm/40 plus mph. Don't even imagine this combo can spin two tires bigger than the 205s that may be on it; 205s if yur lucky.
But
Match your cam to your Static Compression Ratio, so as to get a Dynamic Compression Ratio a tic over 9/1, WITH a tight quench, with the alloy heads and you are guaranteed to have a fun car
Do it right, and it will spin tires, make tremendous torque and great fuel mileage, and it it will do it on 87E10 gas.
Do it wrong, and you'll be burning best gas, having a dog off the line, but with the 2.73s; you'll have a great passing gear at 40/45 mph.
Ask me how I know.
I'll tell ya; cuz I did it twice with same results. My loss is your gain.
Note-1
That 340cam, in already 4 degrees advanced, has an ICA of 64*..
To make a 9.0 Dcr will require an Scr of 11.3. and an SCR of 11.3 requires a maximum total chamber size of about 64.3 cc.
If the pistons are down at the usual .057, that is already 11.4cc.
The 038 gaskets will not survive this pressure without special prep, so yur gonna have to use the .039 Fellpros, making your Q already .096, which is more that double of where it needs to be. But, that gasket is 8.6cc IIRC.
So far then, we are up to 20cc, so the heads are gonna need to be 44.3cc. It doesn't really matter tho, cuz there ain't no Q with is combo.
To get the Q you need, the pistons have to be up at the tops of the bores for an .039 gasket. for a deck clearance of zero, and a Q of .039, which is already baggy. But these pistons will need some eyebrows so lets call them 5cc, and the 8.6 gasket totals 13.6cc so now, the heads can be up to 50.7cc, to run the 64*Ica.
The next smaller Ica might be 61*Ica, and it will run at 11.1 Scr, for a total of 65.6cc, and now the heads can be 52cc
There is a dozen ways to skin this cat, once the pistons are up at the decks with a tight Q, but the 340 cam should not be one of them. I guarantee you will not be sorry, after the tune is in.
And like has already been said, the 2.76s gotta go sooner or later. Whereas;
IMO, if you get the pressure up to a minimum 180psi , the 2000 stall can stay.
But if the convertor has not yet been ordered, I would wait until you know exactly how much cylinder pressure your 318 is making. The more it makes, the less stall she'll need, for a streeter.