NHRA's Ned Wallser said the NHRA did its due dilligence on the possibility of integrating Mountain Motor Pro Stockers in the 500-inch program but in the end, finding common ground would be expensive  for both. 

Integrating the Mountain Motor Pro Stockers into NHRA's Pro Stock division looked good on paper. Unfortunately, that paper wasn't a bank statement.

Citing the expense of bringing the two different styles of Pro Stock together means it won't happen, according to Ned Walliser, NHRA's Vice President of Competition.

"Mountain Motor will not be integrated into the current Pro Stock category, but there is an opportunity for potential exhibitions down the road," Walliser said. "That could be as early as 2019."

NHRA hasn't ruled out the idea that Mountain Motor Pro Stock could become an official series in the years to come, much like Pro Modified is today.

"We’ve certainly got to walk before we can run," Walliser said. "We don’t even know if these guys would be interested in coming out with us. So we’ll investigate that, we’ll communicate with them and see where we go."

The determining factor in not mixing the large displacement engines and the 500-inch traditional powerplants was the result of a recent test with an unidentified mountain motor car at the Texas Motorplex.

The mountain motor car had 200 pounds added to it.

"We ran at 2,605 - 2,610, put them on Sunoco SR18 fuel, took away the C16 and put them on a small Pro Stock Goodyear tire and we’re still not close," Walliser said. "We thought we’d be a lot closer than what we were."

Reportedly the test car was .07 quicker than the quickest 500-inch Pro  Stockers. The car reportedly ran a 6.53 in the heat of the day.

In 1988, the IHRA ran a combined Pro Stock class and evened the field by adding 250 pounds to the Mountain Motor entries. This time, Walliser said, it would take more than a weight addition, each option he said would have cost the teams more money.

"It certainly wasn’t for a lack of effort," Walliser explained. "We thought we could be closer in elapsed time with the things we did. There’s obviously other opportunities to take advantage of to get them closer, but to the degree that we would have to spend on either side of the fence, we just don’t see it economically feasible."