newish to me built 340 valiant feels sluggish. Timing?

My Eddies, on a street 360, at 10.7Scr, 8.6Dcr, will pull with no perceptible difference, with power timing anywhere in the range of 30* to 34* . And does it on 87E10.It likes initial anywhere in the range of 14 to 20. It likes a mellow rate; all in by 3600ish.
It likes 20* for cold starts(no choke) . And has a sweet idle at 14*. I have a 2-stage rate of advance that kicks the first 14* to 16* in by 2600ish, and then slows down the last 4*. Thats how I get around on 87.The V-can is 20*,hooked to the sparkport and,all in by (IIRC)16inches.I bring in as quick as possible, to supplant the mechanical, for smooth,mellow cruising and part-throttle torque.Cruise timing in O/D is 2100@60mph@ about 54*All timings in.
I have a dash-mounted dial-back timing device that has a range of 15 degrees. So I can change timing from the cabin.

I wont say the 650 is too small, but when I switched to a 750DP, I noticed a marked improvement.The performance of my combo with a 600vac was, rather dissappointing.
My quench is set to about .034.The cam is an old Hughes HE3237 with 1.6 arms.
Timings are always,always, set with the V-can defeated.
I have a stick car with a 3.09low and 3.55s. Goes 93 in the 1/8. In that range,Sluggish it is not.

Having said all that, I dont think timing is your issue. But I do think, we need to get your timing squared away first.
And the very next thing would be a compression test.

That cam at 226*,234*,110LSA, should be very torquey.I know the 223/230/110, that I had (my favorite,so far)was.So if your cylinder pressure is down,this is how it manifests: soft out of the gate, and a kick in the pants,a little further down the road.The usual way around that is a higher stall TC.So lets see the compression numbers.

Timing "is set at 20 degrees advance and 10 additional degrees vacuum advance that comes on relatively slowly with full advance at 3k where it does seem to get a little extra kick in the pants."
I cant get sense out of this.
The 20*initial is good, if a little much.
The all in by 3K is probably ok with 93octane
But the 10 additional with vacuum is out in left field.