BTW I have a 1979 Chevy Nova rear end with 2.73 gears and I can cruise all day long at 65 -70 or better. BTW original 235.
With the stock transmission? If so, is your tallest gear ratio 1.00? I thought about putting the T5 behind the stock engine in mine, but I highly doubt it even has enough power to take advantage of overdrive unless I'm going down hill.
