We spoke to Isaiah 16 months after he lost most of his left leg in a car crash ... and he told us he's planning on hittin' the track in hopes of crushing the 2020, 2024 and 2028 Summer Paralympics.

"If they let me on the track, I'm goin' for the gold, period."

Pead says he's still in the early stages -- getting a prosthesis and sponsorship -- but he's confident everything will come together.

If and when it does, the ex-Rams and Dolphins RB says he's gunnin' for the podium in the 400 -- an event he dominated back when he was a high school sprinter.

As for his long-term goals -- "3 gold medals, 3 Paralympics. God willing, that's a hell of a career right there."