Jack Roush and Robert Yates building NASCAR racing engines together is like North Carolina and Texas forming a partnership to make barbecue. Nobody thought they’d ever see it.

Roush and Yates are gearheads to the core. Both have been tinkering with engines since they were old enough to hold a screwdriver. Roush has referred to a well-tuned engine as a symphony. Yates has made motors rumble with power since he was a teenager hot-rodding around on the streets of Charlotte, N.C.

In NASCAR, they’ve been sibling rivals, elbowing each other out of the way trying to get the bigger share of Ford’s financial support over the years.

“I have certainly had respect for him and I hope he’s had respect for me,” Roush said of Yates. “But from the beginning of the racing season until the end we wouldn’t talk to one another. We wouldn’t acknowledge one another. We wouldn’t have eye contact. We wouldn’t shake hands. By all means, we wouldn’t wish one another good luck.”

But now, one weekend into the 2004 Nextel Cup season, the big story is the success of a Roush-Yates partnership that now has all the engines for their Ford teams coming out of the same shop in Mooresville, N.C.

Dale Jarrett won Saturday’s Budweiser Shootout with a “Yoush” engine. Sunday, Greg Biffle and Elliott Sadler got the front-row starting spots for the Daytona 500 and Ricky Rudd and Dale Jarrett also had top-five qualifying speeds with “Rates” power under their hoods.

“Robert Yates has always had great horsepower and Jack Roush has always had great fuel mileage,” Sadler said. “You put those two together and … we’re going to have a team to be reckoned with.”

The concept certainly makes sense. Dodge’s “one-team” approach to developing cars and engines it used when the company returned to Cup racing set the model. Toyota, in getting its NASCAR Truck series program up and running, is refining the process.

It seems, therefore, an obvious step for Ford to get its two remaining top-tier team owners to work together instead of spending its dollars twice. An opportunity arose when Roush decided to move his NASCAR engine operation from Livonia, Mich., to the Charlotte area toward the end of last year. Instead of building a shop of his own, Roush bought 50 percent of Yates’ engine-building operations, thus merging the two shops into one.

Ford teams have new NASCAR-approved nose and tail sections on the body of their Taurus this year, the first major revisions since the model was introduced in 1998. The teams also are working a new cylinder head into their engines — a major project the Yates-Roush engine group now must handle in concert as part of the new arrangement.

“We were in (Las) Vegas a couple of weeks ago testing and Jack and Robert were there talking throughout the entire time that we were there,” Jarrett said.

Asked if he ever thought he would see that, Jarrett said, “Not in a calm way, no.”

When the teams tested at Daytona in January, the Yates teams applied tuning techniques suggested by the Roush folks and their engines gained power. Jarrett used that power to hold off Dale Earnhardt Jr. in the Bud Shootout.

After Biffle’s pole-winning run Sunday, Roush said the winter since the engine merger took effect in late November has been like “an Easter egg hunt.”

“We’ve been taking things apart and seeing how they work and just putting the best of both together,” Roush said. “There have been a lot of things that I hadn’t thought about that I saw that they had done very well and, to their surprise, a number of things they saw that the Roush guys had done better than they had thought.”

One weekend does not a season make. The success of this venture will be measured in race victories and in how the partnership’s engines endure a 36-race season.

“To be successful in racing, you have to be selfish,” Roush driver Jeff Burton said. “But to be successful in today’s environment, you have to be open. It’s hard to do both.”

So far, though, so good.

“It might have been a little weird at first,” Sadler said after Sunday’s Daytona 500 qualifying. “But we were just down there in Victory Lane and Jack and Robert were shaking hands and smiling ear to ear.”

What is next? Coke and Pepsi joining forces?