It will be a hot rod show and probably the subject of hot debate.

City commissioners on Tuesday night agreed to close down the portion of Massachusetts Street that runs through South Park on Oct. 8 for the Rev it Up! Hot Rod Hullaballoo, which will serve as a fundraiser for the Big Brothers Big Sisters program.

Commissioners approved the closing on a 3-2 vote despite Downtown Lawrence Inc. formally objecting to the plan, citing concerns that closing the street on a Saturday would make it difficult for shoppers to get downtown.

But supporters of the event, which is expected to raise $5,000 to $10,000 for Big Brothers Big Sisters, argued the event would bring new people to downtown, who likely would stay most of the day and into the evening.

Narrowly, that argument won the day at City Hall. Mayor Aron Cromwell and Commissioners Hugh Carter and Mike Dever supported the proposal.

“My gut just tells me that events like this are good for downtown,” Dever said.

Dever and Carter also said they were underwhelmed by information presented by Downtown Lawrence Inc. that recommended against the street closure. Both Carter and Dever noted that a representative with Big Brothers Big Sisters received signatures of support for the event from 22 of the 25 downtown businesses that it approached. Downtown Lawrence Inc., Carter and Dever noted, didn’t do a full survey of its membership.

“I would like to hear from more than just a few downtown merchants say they are against this,” Carter said.

Commissioner Mike Amyx and Bob Schumm, who both own businesses on Massachusetts Street, voted against the street closure.

“Unless these events really, really work and bring in a lot of people, it is hard to capture the amount of money these businesses lose by having the street closed on a Saturday,” said Amyx, who owns a barber shop.

Both Amyx and Schumm — and Downtown Lawrence Inc. — said they would be more supportive of the request if the event were for a Sunday. But Stephen Chronister, an organizer of the event, said they feared moving the event to a Sunday would greatly reduce the number of car owners who would participate.