Carl Lewis -- one of the greatest U.S. track athletes EVER -- says he would've eaten the 40-yard dash alive ... telling TMZ Sports his time would've been in the THREES!!!
"Track guys that run it, run it under 4. So, under 4 seconds. Yeah."
Obviously, that time is BLAZING fast ... in the NFL combine last month, only six guys even broke the 4.40 mark.
In fact, the fastest dude in the entire event was Mississippi safety Zedrick Woods -- who clocked in an official time of 4.29.
But, Lewis tells us even though he's never run it -- he's pretty sure he could've gotten into the 3s ... telling us that's just what elite track guys do.
Think he's exaggerating? Maybe just a little ... current U.S. track star Christian Coleman took a swing at the 40 in 2017 -- and while he set it on fire -- his time was just out of the 3-second range at 4.12.
BUT ... Usain Bolt DID just run a 4.22 at the NFL's event a couple of weeks ago, and that was without proper training AND in street clothes ... two years into his retirement.