Are 3.55 gears a good choice?

In my 64 Signet, I run 3:55's with 245-60-14 rear tires and a push button 727. I've really got to run a higher ratio like 3:23 or 2:94's to satisfy my cruising speed when actually traveling. Around town they are awesome but puts a damper on visiting friends 2 and 300 miles from home. I guess I could do a trans swap with an OD but I love the overall presence of the buttons. Without an OD, it is what it is with little to no advantage as to gas mileage and cruising speeds at low RPM's. My truck has a T56 w/ 3:42 rear and cruises at 2000 rpm 90mph in sixth..