McNamara, who gave seven players their first caps in Wrexham, said: "We don't get too many games to experiment. We may make changes."
Rampant England delight McNamara
"We've got some very good players who didn't play against Wales, but it's a two-match series now against France," he added.
"I'm sure they've got some motivation to come and play England after we've not played them for a while."
With four tries on his debut, Josh Charnley looks to have done enough to keep his place so Ryan Hall may make way for the return of Tom Briscoe, with McNamara admitting there is little to choose between the wingers.
"It's virtually a toss of a coin to decide who plays those positions," he said. "Josh has been in tremendous form for his club and got the nod this time."
McNamara is still monitoring the fitness of Wigan full-back Sam Tomkins, Castleford half-back Rangi Chase and Warrington utility player Stefan Ratchford.
Tomkins missed the end of the Super League season, as well as Saturday's opening international, with a knee injury while Chase picked up a groin injury on England's training camp in South Africa and Ratchford was not considered for the Wales game because of illness.
Chase was initially ruled out of the tournament but a second scan showed the injury was not as serious as first feared and he reported back to the England camp in Loughborough today.
Fixtures (all times GMT)
Saturday 20 October:
France 20-6 Wales
Saturday 27 October:
Wales 12-80 England
Saturday 3 November:
England v France, Craven Park, 14:30
Saturday 11 November:
Final, Salford City Stadium, 17:00
Warrington's Richie Myler profited from the absence of Chase and he is hoping to get the nod to continue in the number seven jersey against the French.
"Hopefully, fingers crossed," Myler said. "I was part of a good side. They played well around me and helped my game.
"If I'm selected again this week, I'll be over the moon and I'll give my best again.
"We've got two more games, it's like a mini Test series against France, and everyone wants to be involved."
One man hoping to keep his place is veteran forward Adrian Morley, who returned to the international scene to make his 51st appearance.
"I really enjoyed it," said the 35-year-old Warrington captain. "After being overlooked for the Exiles games in mid-season, it was a goal of mine to make the squad at the end of the year.
"Thankfully I got in the squad and I've loved every minute of the last two weeks building up to the game."
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