Rallyes-New vs OEM

Both of those tire sizes figure out to be ~ 25.5" tall. What gear you running and automatic or standard tranny? Mine has 489/3.23:1 Sure Grip with 4spd. Wondering about 1st gear cruising speed when "Dragging Main". 25.5" tire w/3.23 looks to be ~ 7.5 mph @ 850 rpm with 2.66 ratio first gear. Hoping not to have to constantly be on/off the clutch. Didn't mind it when I was in my teens but 40+ years older now. Haha.