Build suggestions for 340?

This post is all about low-rpm power with a manual trans

looking back; my iterations had VPs of 142,160, and 154.
All of these were enough to initiate a spin with 295s and carry it all the way thru first gear, with a starter-gear as small as 2.66 x3.55= 9.44
But the 142VP needed some help by way of rpm to get started, whereas the 160VP would bust them loose at under 2000rpm with the line-loc engaged, and then I could idle it right down; which was always a hit at a stoplight.
Looking back, the 142 wasn't as bad as I thought. It was just not what I was expecting nor what I wanted, and the lack of slow-running just sealed the deal. I could have lived with it using more rear gear. But living 20 minutes by hiway from the nearest urban center, and it being my DD, the fuel-economy was atrocious, even with the 3.55s I wanted to run.. I moved the cam a couple of times, but it was hardly worth it.
That said, I see no real downside to a VP of 142.... when coupled to the right application, and a clutch with a 2.66 x 3.23= 8.59 starter gear is not it. I would guess, based on my experience, that a starter-gear of 2.66 x 3.91=10.37 would be close. You can get about this, with a Commando box, 3.09 x 3.23= 9.98 . But that does nothing for second gear. You are still stuck with the same 1.92 x 3.23= 6.20 and your 340 will struggle with that, even at VP of 142 if you short shift it.
The problem for the 340 is getting to a VP of 140 or more, with open chamber,iron heads, working within the confines of pumpgas, it just cannot be done with any performance type cam.
The 268 Mopar cam is a good size for a streeter, but the 114LSA and the long slow ramps, kill pressure, and the VP with it. And therein lies the problem.

>Here is your 340, Ica of 64*,(268cam)still 800ft
Static compression ratio of 10.5:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 8.37:1 .
Your dynamic cranking pressure is 169.18 PSI.
V/P (Volume to Pressure Index) is 134
The VP looks fairly good at 134, but Usually, you cannot run 169psi on pumpgas. However,on this cam, the intake valves really are not yet closed, so many times you might be able to adjust the tune to get away with it. But you will have to forever run best gas.

>Lets change the Ica to 68, to more accurately reflect what the Ica might be, when rated as, say .006 tappet rise; and I get.
Static compression ratio of 10.5:1.
Effective stroke is 2.47 inches.
Your dynamic compression ratio is 8.08:1 .
Your dynamic cranking pressure is 161.41 PSI.
V/P (Volume to Pressure Index) is 123
SAME cam, SAME install, just adjusted as said above.
ok so there is the pressure you want, but the VP has dropped into the basement again, which will more accurately reflect what you will feel at low rpm.
There is no getting around this. You cannot increase the VP without also increasing the pressure. And you cannot run more pressure without having to limit your timing. If you drop the compression ratio; both numbers will fall.
>So these numbers, namely 161/123 are very nearly the best you can expect with open-chamber iron heads, and a 268 cam.

Now comes the game changer;
some FABO members say they are running up to 200psi in strokers!, on pump gas, with alloy heads. I myself have run 185 psi and more, on 87E10.
Not cheap I know, but when you consider that you can keep the 3.23s, and keep the 2.66box, and run just about any cam or pressure that you want to, the flexibility is so worth it. The better ports will be worth at least one cam size and a swap to a solid-lifter cam, will open up both ends.

Here is your 340 with alloy heads and an Ica of 66*
Static compression ratio of 11.3:1.
Effective stroke is 2.52 inches.
Your dynamic compression ratio is 8.83:1 .
Your dynamic cranking pressure is 181.61 PSI.
V/P (Volume to Pressure Index) is 141
adequate VP, lots of pressure; that might be a 280 cam......., see what I mean?

>Lets take some cam out, and keep the pressure close to 180 for 87E10.
One cam smaller/ Ica of 62*
Static compression ratio of 10.9:1.
Effective stroke is 2.61 inches.
Your dynamic compression ratio is 8.79:1 .
Your dynamic cranking pressure is 180.52 PSI.
V/P (Volume to Pressure Index) is 145
see the VP climbing

> one more smaller cam; Ica of 58*
Static compression ratio of 10.5:1.
Effective stroke is 2.70 inches.
Your dynamic compression ratio is 8.74:1 .
Your dynamic cranking pressure is 179.17 PSI.
V/P (Volume to Pressure Index) is 149
Still more VP, and back to 10.5 Scr.. 149 is a lot of VP, and you would be sure to have a lotta fun with it.

Each cam size smaller will bring the power down about 200 rpm to work with the 3.23s. But of course the power will be some 15 hp less per cam, is my guess. You can get some of that back by tightening up the LSA. and/or increasing the lift.
A solid lifter cam more or less requires an adjustable valve gear, at additional cost.
Fun with the calculator. I have been impressed with the
Wallace Racing: Dynamic Compression Ratio Calculator