The idea of Cummins parts in a Caterpillar machine seems odd, but the shrinking world of industry consolidation will result in the use of Cummins-sourced selective catalytic reduction equipment on the Navistar-supplied diesels in Cat vocational trucks.

That doesn't bother George Taylor, director of Cat's Global On-Highway Truck Group. Cat dealer technicians will be trained to work on the urea injection equipment, just as they now maintain and repair current CT-660 components from various suppliers, he said.

Will the Cummins-red SCR gear be painted over with Cat yellow, as Navistar's gray engines now are for use by Cat? We'll see. But you can buy Cat trucks in red, blue, purple, green and almost any other color you want, even if some loyal customers specify Cat yellow.

Sales of Caterpillar's CT-660 trucks and tractors are going well, Taylor reported. Company policy prevented him from disclosing sales numbers, but he said they represent the slow, steady growth that fits with Cat's historic long-term strategy.

And Taylor is fine with the announced closing of Navistar's Garland, Texas, plant, which builds the Cat Trucks.

"Caterpillar as a global company has always spent a lot of time balancing production worldwide," he said. "And that the company [Navistar] is doing this to improve its health is a positive."

"The plan is to move production of the truck to Escobedo (in Mexico). Its an ISO plant and produces some of the best quality. We will go through a ramp down and a ramp up, probably in the March-April 2013 time frame," he said.

About that time Cat will phase in the SCR aftreatment equipment, which will come from Cummins Emissions Solutions. Navistar will also begin applying the gear to its own diesels.

Most CT-660s now get the 12.4-liter diesel that Navistar, which builds it, has named MaxxForce 13 and Cat calls the CT-13. Other Cat trucks get the 10.5-liter MaxxForce 11/CT-11.

However, Navistar is dropping the MaxxForce 15, which was due to be offered in the Cat Trucks. Instead it's using the ISX15 from Cummins in its Internationals. Using that in Cat trucks would be going too far. So what will Cat do for a big-block engine? They're not saying.

The industry is increasingly moving toward 13-liter engines anyway, Taylor noted. There are now more 13s than 15s sold industry wide. That's true with certain truck builders, who all have proprietary 13-liter-class diesels that they've made standard in many Class 8 models.

Some predicted the trend to the smaller size, even referring to their own 13s as "big-block" when that used to mean something with larger displacement, like 14s and 15s. The ones most enthusiastic about 13s had no 15s to sell, and that included Navistar until it relented about SCR and turned to Cummins for help with it, and for the ISX15 that some customers want.

To meet strict exhaust emissions limits, engineers at the builders have made great advances in combustion technology and electronic controls. These have also made 13-liter diesels far more powerful than in the olden days, when 400 or 430 horsepower was about it. Now the 13s make as much as 475, 485 and even 500 horses, with torque to match. Is any more power needed in a dump or mixer truck?

So maybe Cat doesn't need a 15-liter engine after all. Taylor didn't say that, but he did say, "On the 15th, will have an announce something by the end of this year.