8" converter on the highway ??

70-80 mph! You have an overdrive?
Nope. I usually follow my wife hard to keep up with her! lol but it I do it 4.10 gear with 28.5 tires. I can’t remember the rpm exactly but 3200 or 3400 sounds about right. You have to also remember back in the day with a 3.23 and 24 inch tires 70 mph was about 3200 and that’s what it was. A short stroke 340 with a bit of a cam loves rpm. This is why back then 100,000 miles your **** was wore out.