Time for new engine in 72 Swinger - What Would You Do?

5.9 magnum , carb conversion,,stock ,weak cam, already 320 hp and more than 400 ft-pd of torque ,very cheap built $$$$$

...OR : 400 + hp and 440 TQ with good cam and 600' lift valve springs, dual plane intake ,750 cfm carb and less than 2000 $