The problem with a 3.07 is that you won't be able to downshift on the highway and the engine is running way off it's horsepower peak.

At 70 mph, the engine is turning 2983 rpm with a manual transmission in high gear. If you wish to downshift to third, you'd be turning about 4500 rpm in third. You'd have the full 67 hp at this point, but the engine won't be very pleased if you want to take it to 75 mph........or more.

Due to the very low horsepower available, the engine needs to stay close to it's horsepower peak on the highway............or suffer reduced road speed as a consequence.

The vehicle would be limited to about 70 mph with the 3.07 using third gear. In high gear, it would probably make a slightly higher road speed given sufficient time, but could not climb the slightest grade.

The 3.46 might be an acceptable compromise.........but, in this situation, third gear is not an option.