Under his carrot crop of hair, the grin of the Rev. Filbert Moore looks as if it was cut from an October jack-o-lantern, and an earnest one at that.

The smile is ever-present, a constant symbol for the people of rural Poolesville, Md., who are working with Mr. Moore to win approval for a Western Montgomery County Community Life Center.

Two years ago, Mrs. Moore gave up his Presbyterian pastorate in Poolesville to help lead the community of about 3,200 toward his dream of a town center. It has since become a crusade.

"You have to seriously question the motives of anyone who opposes this project," Mr. Moore asserts. "We all have labored very hard and sacrificed and prayed for this center."

Mr. Moore was much less sanctimonious when he appeared before the Montgomery County delegation in Annapolis last week: to ask for $400,000 from the state and to quiet those who oppose the project.

Mr. Moore is working on what he calls a "revolutionary concept" for a "full life cycle center" which, when committed to paper, is actually three new wings built on to a junior and senior high school.

For $800,000 (half from the state, alf from the county). Mr. Moore says he can construct a swimming pool in one wing and library in another. The third would be built by doctors for their own offices.

To get his idea off the ground. Mr. Moore has traveled "as far away as Georgia," forsaken a salary save occasional donations from the community and other pastors. He has lobbied first his town council, which was won over, then his county government, which is divided, and he has now marched to the state level, like Robert Preston in the Music Man, to sell his idea and concept to the General Assembly.

"Basically this comes from my Christian background. I was put on this earth to help people and I feel like Louis Pasteur who is this close to discovering a concept whose time has come," explains Mr. Moore.

Living off "the $50 and $100 people slip to us," Mr. Moore has developed what he calls the "total life cycle center concept." By constructing a medical center, a library and recreation facilities onto local small-town high schools, Mr. Moore says he can rein-state the family and save American values.

"If all schools in the state were designed as total family facilities it would save millions and millions of dollars; with $800,000 you can design a center for the whole human lift cycle," Mr. Moore explains. "We're concerned about strengthening the family, saving the tax dollars and . . . energy. When you have to drive far away for medical services you waste energy."

All thing considered, it would seem hard to disapprove of Mr. Moore's project.

Yet the old-timers of Poolesville are fighting the project. the town is already in something of a financial bind, there isn't enough sewer capacity for the buildings already lining Poolesville's streets. In testimony last week, the residents said if the state was to give Poolesville funds for any project, they would prefer sewers. Residents also questioned who would pay for the operating expenses of the center - the county or the town.

Charles Elgin, a third-generating Poolesville resident, not only opposes the center because "there are other things we need like sewers" but questions Moore's motives. He and other Poolsville residents who came to testify against the center suggested that "the center was one man's campaign to be a well-paid director of the center."

Mr. Moore rose to the challenge and told the delegation that even if offered the job of director of the center that has yet to be built, he may decline.

"The only reason we yhe and his wife) have committed our lives to this county is for our ministry," Mr. Moore said. "There comes a point where you can give all you can give and then you may have to leave. If this idea isn't accepted, well, like Jesus said, when they don't hear you, you shake the dust from your feet and go elsewhere."

The Montgomery County delegation has been assigned the duty of deciding the merits of Mr. Moore's project. If the delegation approves of the $400,000 proposal the General Assembly most likely will grant its approval.

In the meantime, the delegation must decide if the center is truly a "revolutionary" and worthwhile concept.

And with the stakes defined as they have been defined, the delegation members might feel as if they are caught between the devil and the deep blue sea.