318 LA torque?

Torque in a NA engine is mainly tied to displacement.
The average engine a hobbyist will have puts out about 1.1 to 1.25 lbs-ft per cid, 350 to 400 lbs-ft at the crank for a 318.

To me torque is an odd goal.
Torque is basically a snapshop of one revolution and the main factor that decides peak torque is VE%.
Power or HP is all the revolutions (rpm). added up.
What your really talking about is usable powerband.

For race engine under 3000 rpm is of little concern most of the time. For a street engine idle to 3000 rpm is the most important especially for a tow truck. Problem is theres little to help over stock low power engine other than low restriction exhaust and cr. But you can stretch the powerband by choosing part that will give up little or even add down low will adding useable power above 3000 rpm.

Hp is a function of torque and rpm, street engines are limited to usable rpm so the only way to greatly increase power in the idle to 5500 rpm range is displacement. Or a power adder.