Gilliland and Bayne were the only drivers who hit the 200 mph mark at Daytona International Speedway. Gilliland's best lap was recorded at 200.138 mph, while Bayne's top lap was just a tick slower at 200.129 mph.
Bayne stunned the auto racing world last year when he won the Daytona 500 one day after he turned 20 years old.
"We've got a fast race car again," he said. "I'm confident that our car is going to be stout and one to contend with in the 500."
Following Gilliland and Bayne on the speed charts were their fellow Ford drivers Ricky Stenhouse Jr. and Aric Almirola.
Fords have been impressive throughout this year's Speedweeks at Daytona. Last Sunday, Roush Fenway Racing teammates Carl Edwards and Greg Biffle put their Fords on the front starting row for the 54th running of NASCAR's most prestigious race of the season.
Thirty-six of the 43 Sprint Cup Series teams that qualified for the Daytona 500 participated in the one-and-a-half session. Those drivers not turning laps around the 2.5-mile superspeedway included: Brad Keselowski, Denny Hamlin and Tony Stewart, the defending series champion.
Stewart, who won the first of Thursday's Gatorade Duel twin qualifying races, is hoping to win the Daytona 500 for the first time in 14 attempts.
Jimmie Johnson's team had planned on running a handful of laps in practice but opted not to take their car on the track.
"We're really happy with our car," Johnson said. "From the [Budweiser] Shootout car to this car, they've been fast. They drive really well. I think we showed a lot of strength in the Shootout, but unfortunately, we were caught up in a late-race wreck. Then in the [Gatorade] Duel, we showed a lot of strength as well. I'm very excited about the Daytona 500, and I can't wait to race."
Sunday's Daytona 500 is scheduled to start just after 1:00 p.m. (et). However, weather could be an issue. According to the National Weather Service, the forecast for the Daytona Beach area is calling for a 70 percent chance of rain and wind gusts as high as 25 mph.
"I feel like with the Daytona 500 and the fact that we have lights here, and we can run late into the evening, if we do have rain, we'll be here getting all the miles in," Johnson said. "If we don't get on track at all, I'll stay here all week and have a shot at taking that trophy [Harley J. Earl Trophy] home. So we'll just play it by ear."
The Daytona 500 has never been postponed in the 54-year history of this event.