340 Engine Shake

What's wrong with using the earlier, smaller cam? Put some solid lifters on it and call it done; you'll never have to worry about an annoying tic again, cuz you'll have 16 of 'em.... lol.
Plus the earlier closing intake will net you more CCP and a stronger bottom end to replace that which you lost, when you left the automatic behind.
Plus, a wider power-band to cover that 3+1 gear spread.
Plus the smaller cam will like the overdrive more.
Plus the less overlap/earlier closing intake valve, will make the EFI happier.

How much of the "ugliness" in the cylinders is pits and how much is just staining? What I mean is maybe a couple of thou is all you need to clean it up.
Hypers are usually installed pretty tight.... like .002. Maybe you can get away with .003/.004.
My KB 107 hypers are running at .0045 clearance, and the engine makes great power, with file-fit plasma-moly rings.. .... jus saying.
I would rock that 340, with looser skirts. and file-fit rings.

I would forget about roller lifters, too; I haven't been able to kill my Hughes HE3038AL cam since 2004. Like RRR says; "rollers are over-rated." and IMO, especially hydros.
My Hughes 3037 is 276/286/110 and 230/[email protected] with lifts of .549/.571 @1.6 arms. I used their best Hydros at the time. I used to rev it to 7000/7200 all the time. I ran them at about .5 turn preload. I run a 750DP.

The thing is, with a 4-speed, your idle speed and gears will determine your minimum road speed. With 26.6"tires, 4.10s and a 3.09 low gear, your roadspeed maths out to 6.25 mph @1000rpm; 700 is still 4.4mph and too fast to walk alongside. To parade it, you need to get down to a max of 3.5 mph, which is 560rpm. To run down there, your Idle-Timing is gonna need to be down around 5* advanced.
My 367 will idle down there all day with the 750DP, but it wasn't easy getting it to do that, with the 230* cam. I can't see it being any easier with the Fi-tech. Nor with what is now, a 350 cubic inch short-stroke engine.
It was even better with my previous HE2430AL cam,
270/276/110, 223/[email protected] and .538/[email protected]. I remember that cam with much fondness.

BTW; it's not the tight cam centerline per se that the EFI doesn't like; rather, it is the large amount of overlap, and especially the low vacuum signal of the late-closing intake that bothers her.
Solid lifters let you run a lil more cam for the same vacuum signal, and part of the "more cam" can be in the overlap. But in my case, running 3.55 gears, the 230 cam really is out of it's element, and the only thing that saves my combo is the 180psi CCP. The previous 223* cam was much happier about the 3.55s.

So lets look at the numbers.
First, the current 230* cam, in at 107; , then the previous 223* cam in at 105*.
the cam events are;
>>276 intake/114 compression/105 power/286 exhaust/61overlap/Ica of 66*
>>270 intake/120 compression/107 power/276 exhaust/53overlap/Ica of 60*
Notice that the 223 cam makes 120 verses 114 compression. this translates to a CCP increase of about 10psi, from 177 to 187, in my case. This is a big increase and it affects the Idle vacuum a lot.
Next notice the Power-cycle has gone from 105 to 107, not much difference here, but the engine has gained 2* more time to extract energy from the expanding gasses increasing the potential for fuel economy.
Finally, notice that overlap has fallen 8* from 61 to 53; so yeah this cam makes a lil less power, but with a 4-speed you'll be hard pressed to feel it in the first two gears, and I'm half-way thru third before I get it, and only because I previously had a 292/292/108 cam lol. See; my new power peak with the 230 cam, is not 200rpm higher, (say 5200 verses 5000 with the 223cam), but at WOT, she hits 65mph at 5500 at the top of Second gear bang on the power peak. So yeah, she's no slouch, but she ain't fighting the wind yet. With the 223 cam, she was already on the downside of the power curve, but it hardly mattered cuz the tires were usually still spinning.......
Now, because I had CCP to spare, I ran that 223 cam a hair retarded to move the power up a hair and in at 109* I got this;
>>270 intake/116 compression/111 Power/276exhaust/53overlap/ Ica of 64*
Notice I lost 4* of compression, but gained that same 4* now in Power. I just upped the Scr to 11.3 (from 11.0) to get the CCP back.
But that 111* of Power-extraction made a huge increase in Steady-State fuel economy.
After I got the new 230cam tuned up, I sorely missed that 223* cam. I have been waiting since 2004 for that 230 flat-tappet cam to expire......... so I can go back at least to a 223cam, but more likely a 218, cuz I know I can get hiway mpgs well over 30 with double-overdrive........ with a spreadbore carb, and geared for 65= ~1500.
A roller cam won't touch that because of the loooooooooong clearance ramps required to get those heavy lifters in motion. Everybody talks about how the roller cams can be faster at mid lifts and over the nose, but totally ignore the slow-start problem. Like RRR said; "rollers are over-rated". Ima going with a solid flat-tappet. The solids have clearance ramps too, and usually a lil slower than a hydro, but not as slow as a roller, and the solids are lightweight, rev to the moon, and are trouble-free.
I'm just thinking out loud.