[kalbert]

I sure hope you're doing your speed tests on a closed course designed for that kind of activity. Your 35 year old truck does not have the safety or engineering from the factory for high speed stuff.

For starters the rubber and the road need to be up to the task. you need a stable road surface engineered for that kind of abuse. Your typical highway pavement is not engineered for that and can come loose under that stress and cause you to loose control. Next you need tires rated for your weight and that speed, your typical performance tire is rated somewhere around 100mph. Truck tires much less. Driving over the limit of the tire will cause it to separate and come apart. A blowout at 100mph is a death sentence.

You also need aerodynamic enhancements to create enough downforce to keep it from becoming light or airborne. You need a low center of gravity. You need enough power and gear to overcome the down force you add. You need a full cage, harness, and seat. Helmet, fire suit, etc. Pickup truck styling, bench seat with a shoulder strap, leaf springs and mushy SLA wont do 140mph on their own, and will kill you and whoever you hit if you try.

I would guess you dont have the wherewithal to address any of those problems. My suggestion is to abandon your high speed runs and instead work on how fast you can do a 1/4 or 1/8 mile. Do it on a track.