More Torque than Hp?

To have decent low-speed performance with a 340;
and to make a torquey engine,lol, you need to trap the maximum amount of combustible mixture, as early as possible, compress the chit out of it, burn it all up,transfer the energy to the crank for as long as you dare, get rid of it as fast as you can, and then bring in the next charge. Pretty simple really.
Or just get more gears; either in the back or in the trans; it makes no difference. TM ( Torque Multiplication) is King on the street.

I once put a complete 318 top end, cam and all, onto/into a 340. Man that thing was fun,in a 65 V-100 station wagon. That was about 1974. I used Hooker Fenderwells and straight pipes to shorty thrushes and still straight to the back.
That's trapping, compressing, holding for as long as you dare, and then getting rid of it as quickly as possible.
Now, I'm not suggesting you do that; I was a broke-azz kid, and these were what I had accumulated.
Good recipes have already been presented.