Why a 'simple' switch from a Chevy to Ford engine is so difficult

[gnomesayin]

Part of this interview with dirt late model driver Brandon Overton is about his own team and situation, which is of narrow interest. However, it gets into the subject of him having switched from Chevy to Ford engines this season, and I found his responses interesting about how all-encompassing the changes are. Dirt late model suspensions are quite complex and extremely sensitive, so it makes sense why he would say that the power curve and torque differences change literally every element of the setup. Elsewhere in the dirt world, Tony Stewart's sprint car operation has spent multiple years with Ford developing a Ford sprint car engine that they were comfortable putting in the cars, and they're finally running them this year. Many (myself included) wouldn't realize just how much difference there is.

Ford vs Chevy
Dirt Racing Engines

You’re the second driver to tell me that the engine changes the way the car drives. But, I don’t really understand why that would be?

“I’ve notoriously run Chevy’s a lot. Between Randy Cleary Engines and Clements Racing Engines, that’s really the only two motors that I’ve run,” Overton explained.

Overton previously ran Randy Cleary Engines. With the new team, he’s made the switch to Clements Racing Engines as well as to a Ford block.

“So, everything that I’ve built… Notebook and information, has been from Chevy motors.”

“I came over here, they have Fords. We figured out that stuff I ran good with at Tazewell — We go back over there and it’s not that good. We had to change all that stuff.”

But, I don’t understand why exactly? Is it torque?

“A lot of it is torque. The Fords drive really soft. You use a lot of gas.”


“They don’t have as much power in the down low. They tend to not be as hard to hook up. But, in return of that, it drives totally different,” Overton concluded.

“The driver’s throttle position has to be in a much different location from Chevrolet to Ford,”
Harold Holly, crew chief for Brandon Overton explained.

When you first pick up the throttle?

“Well, yes. Basically.”

“I don’t want to give away the numbers. But, it’s got a lot to do with when you initiate the throttle, how the car moves. Up versus forward.”

“The Ford package, basically what he’s telling you is that when he first picks up the throttle, it doesn’t move the car as hard.”

Lift it up on the bars you mean?

“Yup. It doesn’t move the car initially like that. So, it changes every piece of setup that you have. Every load number, everything.”

https://racingnews.co/2019/04/14/br...hevy-engine-differences-in-dirt-track-racing/