Diesel trucks have lots of torque at low RPM so you better off getting one.

its a 30 year old truck with a V6. Id be happy it still runs and wouldn't push it anyway.

The best overall idea to get more torque is buy a truck with more torque.

The only way to really increase torque on that thing is forced induction, but that will finish off your engine, trans, require tuning, and cost a fortune. 

if you wanna go real crazy you can swap in like a 454, but again that'll require ALOT of work and money. 

I'm assuming those last 2 ideas aren't really what you're looking to do anyway. 

What do you need more torque for?

Posted by: @thegrandchawhee

How do I increase torque

Get a diesel truck

How do I increase torque

Buying a new car.

Your car has peak torque (315 NM) at 2,000 rpm - it’s not too bad.

A 2.7 EcoBoost has ~550 NM.

I want to the Impossible for my Truck.

Anything?

With a turbo or super charger, but you have to balance these methods with knowing the limits of your engine, especially with its age and mileage. 

Posted by: @thegrandchawhee

No Diseal

Well the only option is by adding turbo or super charger like others mentioned but they cost a fortune to buy and install. It's an old truck doesn't have enough power to begin with while newer trucks have more power. Do you really need more torque for hauling (which is enough) or you want more horsepower for faster acceleration?

The OBS trucks are great.  From the other comments, I think you get the idea that there's not a simple way to increase torque per se without blowing up the motor.

But that doesn't mean you can't make some small mods to get better performance and maintain reasonable reliability.

First thing is to make sure it's well tuned up.  Before you spend too much $ on it, I'd probably do a quick pressure test (and you can inspect and/or replace the plugs at the same time).  If you are losing compression on 1 or more cylinders, I'd probably get rid of it or start saving up for an engine swap.  (BTW, that's the best way to get more torque.  Lots of aftermarket support for an LS swap, though it is definitely a big investment.

Once you make sure the bones of the block are good, you can start moving through the list...  Make sure you have a clean air filter.  And maybe replace the fuel filter.  I would inspect the throttle body and give it a good cleaning if there is a lot of buildup.  You might also have the fuel pressure tested.  I would also look at upgrading tires; whatever torque numbers you have, you will get better performance if you have good rubber.

Good luck