is the C4 in there a 3 or 4 speed?...all the info I find, leads to me think 3, but t seems like it wants, or needs, to shift again when cruising above 70 MPH
its a 3 speed, no overdrive. You are probably used to overdrive, so thats why you think it needs to shift again. Luckily, a 289 will rev all day without breaking a sweat, so let her rip.