Break out the leather helmets. Or at least the single-bar facemasks.

You can forget about seeing the shotgun, twin and triple receiver sets or even the I-formation when Livermore Falls High School hosts Boothbay Region High School in tonight’s Western Class C football semifinal at Griffin Field. Kickoff is 7 p.m.

The Andies and Seahawks employ offensive schemes from a bygone era and carve up defenses with a post-modern flourish. Livermore Falls’ Wing-T and the Boothbay double-wing have combined for precisely 500 points against a Campbell Conference that struggled to figure out who had the ball and had trouble tackling that person even when they could identify him.

There’s no mystery who will log a lion’s share of the carries for No. 2 Livermore Falls (7-2). All eyes should be on No. 5, senior Mark O’Shea, who leads the league with over 1,300 rushing yards and 18 touchdowns.

Mike Nichols, another senior who made the transition from quarterback to halfback this season, provided an added dimension down the stretch. Nichols complemented O’Shea with 127 yards and a TD in a 34-12 triumph at Traip and added 87 yards in last week’s 20-6 victory over Jay.

“We had a fumble in the third quarter (against Jay), and I don’t know if it was nerves on the part of the younger kids or what, but after that in these type of games you want to put the ball in the hands of your seniors,” said Livermore Falls coach Brad Bishop.

Bishop, who has guided Livermore Falls to five consecutive playoff appearances, proudly proclaims that the Andies are vanilla. No. 3 Boothbay (7-2) might have disputed that notion after watching Livermore Falls quarterback Kevin Gats complete touchdown passes to Nichols and Kyle Stebbins, highlighting a 28-14 victory by the Andies in Week 3.

That win launched a seven-game winning streak, with the Andies pounding the rock behind an experienced front five that features Mike Durrell, Craig Jackman, Dylan Brayley, Donovan Smith and Rory Young. Durrell is a dynamic presence on both lines and on special teams.

Livermore Falls’ two-month roll doesn’t give the Andies any delusions of grandeur. They recognize themselves as a blue-collar bunch that functions best with an early lead.

“The kids work hard,” Bishop said. “We didn’t play well at Traip, despite what the score might indicate (a 34-12 win on Oct. 21), but they bounced back, and it’s a credit to them.”

Boothbay endured a five-game midseason slump, starting with the loss to Livermore Falls, in which its traditionally powerful offense scored two or fewer touchdowns on four occasions.

“Our offense has been a lot like some of the fields we’re played on lately: Stuck in the mud,” said Boothbay coach Tim Rice.

Aches and pains were part of the problem. RB Max Alley and TE Pat Norton were lost to injury. Alley returned in the next-to-last game of the regular season and gave the running game its groove back in authoritative victories over Winthrop (58-24) and Old Orchard Beach (38-6).

QB Roy Arsenault now has three proven chain-movers — Alley, Tim Stover and Dylan Brandt- standing in his shadow on every snap. Stover is a big-play receiving threat out of the backfield to complement 6-foot-4 end Kris Noonan.

Noonan’s falling grab in the end zone as time expired sealed an improbable 14-9 win over Jay in Week 5 and might have saved Boothbay’s season. The Seahawks fell hard at Lisbon a week later, 34-6, then narrowly nudged Dirigo, 14-8, to start its current three-game unbeaten string.

“We got back to basics,” Rice said. “We didn’t want to out-scheme ourselves.”

Defensive backs Arsenault, Noonan, Brandt and Scott Norwood, linebacker Sewall Maddocks and lineman Adam Climo lead a Boothbay defense that must find a way to wrap up the Andies on first and second down.

Livermore Falls makes its living in third-and-3 and fourth-and-1 situations. In their September trip to Boothbay, the Andies hammered out three touchdown drives of more than 10 plays each.