How low are 355 gears

You'll need to know your tire size in inches or at least the width and profile. Like 24.5 inches tall or 195/70/14 for example.

You trans will have a 1.0 high gear so that will give you a 3.23 or 3.55 final drive depending on which way you go.

Let's assume you have 195/70/14 tires. Those should be 24.2 inches tall (plus or minus). at 60 mph the 3.23 will give you 2691rpm, the 3.55 will be 2957 rpm.

I just used a questimate for the tire size but the taller tire you go the lower the rpm will be.