Not all horsepower is created equal, at least if you’re a top Senate tax-writer.  

A draft tax extenders measure released Tuesday, ahead of a Thursday markup package, includes three-year depreciation for race horses, but it leaves out several other targeted tax policies — such as those boosting NASCAR race tracks and the film industry — that might be easy targets for opponents. That’s sparked a pre-emptive spat, even though nothing is locked in stone.  

Finance Committee ranking member Orrin G. Hatch suggested this year’s extenders process bring targeted tax breaks out from hiding.  

“For far too long Washington has acted to extend long-standing tax policy, rarely shining a spotlight on the individual provisions or their impact on the families and businesses that benefit from them,” the Utah Republican said in a statement. “Such dysfunction must come to an end.”  

Finance Chairman Ron Wyden highlighted for reporters the popular big ticket inclusions that would be difficult to wipe out even in a broader overhaul of the complex and convoluted tax code.  

“To just let these extenders continue to be overboard in the ocean would mean that it would be harder in America to create jobs,” the Oregon Democrat said. “We wouldn’t have the incentives, for example, for innovation, for research and development, you wouldn’t have the incentives for renewable energy, you wouldn’t have the incentives for housing — which is a big economic multiplier in much of the country. So, that’s why we’re working to do extenders tomorrow in a bipartisan way.”  

When the chairman’s mark came out for the first version of the bill, which would revive and extend a slew of lapsed tax provisions, the policy wonks dove in looking for winners and losers. Among the discoveries: The legislation would revive the tax provision that allows for depreciating race horses over three years, a favorite of the Kentucky delegation.  

Those in the wind industry weren’t so lucky. The draft leaves out the production tax credit, prompting a quick and predictable rebuke in a statement from Sen. Charles E. Grassley, R-Iowa, a former Finance chairman.  

“There’s no fair rationale for leaving wind energy out of the chairman’s mark. There’s a significant amount of bipartisan, bicameral support for the wind tax provisions. Just last month, 26 senators and 118 House members urged restoring the lapsed provisions,” Grassley said, noting he will work to get the provisions restored.  

Motor sports operators weren’t terribly lucky, either. Gone, at least for now, is a seven-year period associated with recovering costs from facilities, as well as improvements to properties themselves, for race tracks.  

The package also didn’t contain an extension of expensing rules that benefit movie-makers in the motion picture industry, but people familiar with the issue suggested that language seemed like a candidate for addition by amendment.  

Republican Whip John Cornyn of Texas, a Finance Committee member, questioned an approach that would ultimately extend almost everything.  

“I’m hearing that the chairman intends to basically reinstate all of the lapsed provisions, which strikes me as an unfortunate development,” Cornyn said, suggesting there must be a better approach than “just reinstating temporary provisions that seem to never die.”  

Wyden and his committee office also signaled Tuesday that nothing should be assumed from provisions being excluded from the measure going to markup Thursday. He ran through the process, promising he would “obviously” work “closely” with his ranking member.  

“Sen. Hatch and I, and our staffs, pared a number of the extenders back. The senators will have until tomorrow at noon to file their amendments, and then Sen. Hatch and I will get together once more and we will look at all the possibilities for what’s called a modification to the chair’s mark,” Wyden told reporters.  

With a potential legislative free-for-all, that’s when the real fun will begin.