1968 c10 gear ratio for highway

[groundedc10]

I am just looking for everyone's opinion for a good highway gear ratio for my setup. I currently have a 305 with a manual 4 speed. In 4th gear at 60mph the engine is working very hard and in the upper RPM's. I am looking to change my gears so I can cruise on the highway at a higher speed than 60 and not have the engine RPM's so high. I have done some research but don't see any info of anyone with a good setup. Let me know your thoughts. Thanks