How do I give a 1967/68 232 1 bbl more power?

Advance the ignition timing is the best option without spending a lot of money. Years ago one trick was to install lighter springs in the distributor for the centrifugal weights. That kept the base timing at specs but gave you more timing advance sooner as engine speed increased.

If you want to get more involved, look for an offset dowel pin that goes between the camshaft and sprocket. You will make a big change in the "personality" of the engine by changing the cam timing two degrees. Advancing the cam will increase high end torque. Retarding it two degrees will greatly increase low end torque. That is done for motor homes to help them pull away from stop signs. It is also a characteristic of "gas mileage" cams. I put one in an old '69 Chrysler 318 in a heavy station wagon and could squeal the tires all over the place. Gas mileage did go up too. The trade-off is you lose high-end torque so it takes longer to pull out and pass people. I also had a '78 Dodge police car with a 440 c.I. It was a highway car and with the advanced cam, it took off from a stop like a little 318 but it really took off from 50 mph when you stomped on it at highway speeds.