You can probably get similar power with a set of well-tuned SUs.

The K cam will move the torque curve down the RPM range a bit, and actually make a bit less HP than the D that's in there now. The difference is probably not noticeable in daily driving. Not recommended.

Have a good local shop build a 2-1/4" (minimum) exhaust system with as few bends as possible -- go under the rear axle -- and with the muffler as far back as you can fit it.

You can raise power further by increasing compression -- a thin head gasket and some shaving of the head is better than a regular head gasket and more shaving -- and having someone who knows what he's doing (unlike me) open up the sharp radius in the exhaust ports. And of course, get a good all-angle valve grind while the head's off.

After that, you're looking at some real money...