torque converter question

I don't necessarily agree a converter will not help. Modern converters are marvels of engineering and they can make a huge difference if you communicate honestly with your converter manufacturer. Also, you can quickly identify a lockup transmission if it has a hole in the input shaft of the transmission. Hole in the input shaft = lockup, solid input shaft = non lockup. Getting more grunt from a slant six I like to look at as a challenge. I don't like to call it difficult. I pretty much echo all of the advice so far. More cylinder pressure, bigger exhaust, (you'll want to see what I did here Exhaust Manifold Mod) very careful camshaft choice. I say careful , because with a heavier vehicle like a truck, over camming a slant is even easier to do. They are easy to over cam in the first place, so watch it. You also want a good hot ignition curve. Unless you really raise compression a lot, you can probably get by with having it all in by 2500 RPM. If you end up with say 160 PSI or more, you'll want to limit that to all in by 3000 or 3500 to ward off any possible spark knock. I would say maybe 12-15 initial and 32-34 total in by "somewhere" around 2500-3500 all dependent on what it likes. Contact Ken Heard at Oregon Cams and he can suggest a good grind for you. Send him your core and 89 bucks later you have a cam.