Loomis, Calif., seems an unlikely spot to plot a revolution.

Its 1,500 residents enjoy their little town 25 miles from Sacramento and usually engage in activities no more threatening than an occasional bird hunt.

But Loomis is also the home of Lewis K. Uhler, who has lit a prairie fire of U.S. taxpayer fervor for constitutional change, remaining virtually unknown himself.

Uhler, 48, is founder and president of the 600,000-member National Tax-Limitation Committee and coauthor, with Milton Friedman, of the balanced-budget amendment that has won President Reagan's endorsement and seems on its way to a majority in the Senate.

Ron Dunlap, a Republican who led a fight for spending limits in Washington state in 1980, calls Uhler "the real yeoman" of the balanced-budget fight.

A Yale graduate and hard-working attorney with a Republican bent, Uhler had not seemed the crusader type.

But he said that 3 1/2 years working for then California governor Ronald Reagan, directing the state office of economic opportunity and serving in the human relations agency, taught how "exceedingly difficult" bureaucratic inertia and private interest groups made elimination even of "a community action program that was clearly doing badly."

What was needed, he decided, was an amendment at the federal level that would force congressmen to stifle--or at least mitigate--their urge to give in to their most vocal constituents.

He had a reason for locating his national tax-limitation committee's headquarters and himself in Loomis, so far from everything: He intended to build a grass-roots movement that would influence the powers in Washington through their constituents. Loomis, Uhler said, "had a symbolic importance, but it's also important because you can think better there."

Uhler said he does not believe his amendment can eliminate deficits, but it is at least an attempt to "change the bias . . . so that government does not grow greater than its ability to pay."