"I think a lot of people assume back when I used to race Champ Car that I did a lot of ovals, but I really didn't," said Allmendinger, who last raced an Indy car on an oval in 2006 at Milwaukee, where he finished fourth.
He was at Texas testing in advance of the April 11 Rookie Orientation Program at Indianapolis Motor Speedway, where Allmendinger is scheduled to run the Indianapolis 500 for Penske Racing.
For now, he's still adapting to his return to open-wheel cars, and learned Wednesday he has room for improvement even though he's familiar with the Texas track. Allmendinger ran 10 NASCAR races in a Sprint Cup car at TMS, but said there's not a lot of carryover between the cars.
"I do have a little bit of track knowledge of knowing what the track does, but it's still a lot different," he said. "For me, it's about going to Indy and feeling comfortable in an Indy car going around a fast race track like this. There's a lot of work I've got to do still, just to feel comfortable.
"I feel like the speed will come, but just generally feeling comfortable in the car and feeling like I'm more on top of the car than the car is driving me is something I'm still fighting a lot."
Allmendinger is scheduled to make his IndyCar debut next weekend at Barber Motorsports Park, the only race he's got scheduled with Penske before the Indy 500.
Penske said last weekend he hasn't ruled out running Allmendinger on the street course at Long Beach, but doesn't have the funding put together yet.
Allmendinger is feeling the pressure to perform for Penske and sponsor Izod.
"To be able to have the opportunity, it just means the world to me," he said. "But at the same point, I want to take advantage of it and I don't want to just be here just to be here and say I ran the Indy 500 and a couple of and I got to do a couple of races. To have Izod step on board, and they've been such a huge supporter of the IndyCar Series ... there's a lot of pressure there. And I put a lot of it on myself.
"I don't want to go out there and waste anybody's time, and waste Roger's money. I want to go out there and be up front at the start."