Cam advice for more torque from 340

Yes, you don't NEED to dyno it. Use your backside dyno LOL

On the compression: take the cranking compression readings again and post them as well as your elevation. 3 reasons to do this:
1. Good CR is very important for good low RPM torque... like what you want.
2. If you DO have domed pistons and a 10.5 SCR, with a high associated DCR (dynamic compressin ratio), then you are going to have to be a lot more careful with total ignition timing to avoid detonation.
3. If the SCR and DCR are high, then advancing the cam more will lead you even closer to detonation-land.

So you REALLY need a baseline of what you have BEFORE you go too far with cam and ignition advance .

I would also check the TDC mark on you damper to be sure it is at true TDC for the same reasons.

Then I would time the cam with a dial indicator and degree wheel on intake and exhaust, to find where the intake and exhaust peaks are located. Find the angles for .050" or .100" lift on both closing and opening ramps for one each of intake and exhaust valves, and take the mid-point between these angles as the peak points. This will tell you the LSA and the installed intake centerline. If the cam is advanced already (due to installation or a cam ground with advance built-in), you want to know this before you advance it even further. And you are going to need the dial indicator and degree wheel anyway if you adjust cam timing so do it right to start, plus this will get you the actual cam specs.

This is all to get a proper baseline of what you really have before you start the optimizing of timing, so you don't end up with who-knows-what. Yes, it is a PITA but darn, you have some $$ into this, so it needs a solid approach to tuning.