Low
What gears are you running?. I have 3:42's and at 65 when I hit the passing gear the truck scoots pretty dam quick..Are you kicking it down far enough to catch what they call the passing gear (downshift out of overdrive to second)?. Try the throttle body mod at
www.sshotrods.com under the 96+ 4.3 performance section. Do you have a 4.3? If not the only way your gonna pass quick at 70 with a 4 banger is with A: 4.3

B: Juice :uhoh: or C: Somebody hits you from behind at 100+ :idea: But seriously. Give us some stats on your truck and maybe we can help out more...