Adding to the last post . . . .
Here is a short VIDEO
] of me driving my 1963 C10 with an inline 230. My T5 has a 4.03 first gear and a 3.73 rear axle. You can see that I don’t spend much time in 1st gear. With the 3.07 rear axle and 4.03 first gear you would likely shift at 18 mph when your tach hits 2600 RPMs.
***(Tire diameter does make a difference, but I made the calculations with a common size tire of 235/75R15 with a 28.8” diameter.)
Make note that the shift I make at 2600 RPMs is at 14.8 MPH.
So the 3.07 rear axle makes SOME difference, and a 3.42 would end up between the two.
IMHO, the 3.42 rear axle gear would be a better match for any driving that has occasional hills but the 3.07 would also work well.