So randomly over the years I've tried to find this book using all sorts of keywords, reading release lists by decade, and nothing seems to click.
I'm pretty sure I read it in 1987, give or take a year, but it could have been published 5 years or so before then.
The story: It's around the year 2050, and a 50+ year old(?) janitor is compelled to help a mysterious boy escape from the corporation he is being held captive at one night. Turns out the kid is telepathic and the longer the janitor is around him, the younger he feels.
One memorable scene is where he ends up torturing two security guards in the back of a semi trailer for info using jalapenos/juice in their mouths and eyes.
The only other big scene is the end where the janitor has fixed up a gas burning car to race in the Daytona 500 against all the electric cars, as a distraction until help can arrive, in the form of a newly converted aircraft carrier FTL (faster than light) spaceship.
The cover had a red helicopter either crashing near a house or attacking it, double bladed, with no tail rotors (straight shaft).