What’s the official definition of sleeper? Technically it’s any unsuspecting car with subdued looks, that packs a substantial amount of power under the hood. They’ve come in all shapes and sizes over the years, some of which came from the factory, while many others were built by a determined gearhead in their own garage.

Out went the old SBC, and in went a modified and carbureted 5.3L LS. It's good for high 12's in the quarter with its current configuration.

Take this 1970 Malibu 4-door for instance. It started out in life as a little old lady car equipped with a very pedestrian 2-bbl. 350. It severed as a daily-driven grocery getter up to a few years ago since it was new.The current owner has listed the Malibu on eBay, but not before he swapped out the entire drivetrain for something a bit more powerful.

In this case it would be a carbureted 5.3L LS answering the call for increased performance, and it has gone as fast as 12.93 at 105 mph according to the seller. Not exactly Earth-shattering, but much quicker than the original SBC could’ve gone.

The Malibu still wears it’s original paint and interior well, with the only deviation from the factory appearance being the removal of the vinyl top. However, in keeping with the original style, the roof has since been repainted a contrasting gloss white.

The 5.3L comes complete with a whole host of performance upgrades, and is shifted through a TCI-built TH350 equipped with a 2200rpm stall conveter.

If you’re interested in adding this car to your collection you better jump on it fast because there are only a few days left in the auction. With a reserve price of $9,250 it’s within reach of most gearheads looking for affordable performance. For the full story on this Malibu click here.

Other than the wheels, this '70 Malibu still looks like the lo-po grandma car that it used to be.