My 98 2dr 4 speed auto runs 3000 rpm at exactly 55mph in overdrive. I have 235X75X15 wheels also. Should note that the bigger the tires the faster you may be really going cuz the speedo may be reading lower that the real speed. When I had OEM 205 size tires I was going about 3 mph slower than speedo read, with the 235s I am going about 2 miles an hour faster than speedo reads (checked by radar).
Thats about a 10% speed improvement for same rpms!
That also has an effect on gas mileage. With bigger tires you are going farther than the speedo reads so you are getting better gas mileage than indicated.
