Wheels require balancing.
Bad tires, out of balance , wrong wheels , bad tie rod end.
Might just need a front end alignment or maybe balance and rotate your tires.
Probably wheel balance.
worn front end bushings, the death wobble usually needs track bar bushings but I recommend replacing them all with nylon when you do it.
The fact that it's a piece of junk chevy, get a mustang. Ford all day.
Tires out of balance, bent wheel, or defective tire.
problem with your transmission in 5th gear
Worn steering parts, worn suspension parts, tires out of balance, out of alignment,
Most commonly, this problem is due to a out-of-round tire or a tire that needs a rebalance.
Mine did the same thing. It would get better when I got up to 50+. Turned out to be the CV joint. Replaced the whole axle for around $80(part only).
Tire our of balance or bent wheel. Have your tires rotated and balanced.
warped rotor