Some of the victims reported the abuse to police after reading press reports about Peter Farrands being jailed for seven years in May 2015.
As well as working at Folville Rise Junior School in Leicester, Farrands was a scoutmaster and lay preacher.
The four victims were aged between six and 12 when Farrands abused them.
Sentencing Farrands, Judge Nicholas Dean QC said: "This was a breach of trust as a school teacher and a scoutmaster and the effect continues to haunt the victims.
"The sentence must seem lenient to the victims but they should look at the total sentence."
He pleaded guilty to seven additional charges of indecent assault against boys between 1976 and 1981.
Leicestershire Police said Farrands committed most of his crimes at Folville Rise Junior School.
Det Sgt Hazel Sandall hopes the case will encourage other victims of historical abuse to come forward.
She said: "No matter how old the offender and no matter how many years ago crimes took place, we will conduct a thorough examination of the evidence and will not hesitate to seek charges being brought against perpetrators of crime where evidence is available to us."
Two of the victims came to Leicester Crown Court, where Farrands appeared via video link, to see him sentenced.
The court heard one victim contacted the NSPCC in 2014 and said he had been abused by Farrands and two other people, who he believed have since died.
Some of the boys were assaulted multiple times.
In a statement read out in court, one of the victims said he is still receiving counselling because of what happened.
"There is still a lot of pain," he said.
"I'm still unable to enjoy the simple things like Christmas and birthdays."

Talking to Radio 1 Breakfast show host, Nick Grimshaw, Cowell revealed his 88-year-old mum still calls the shots.
"She still loves to tell me off," the X Factor boss confessed.
"The worst thing she can say to me if I'm got my friends round is, 'Simon stop showing off' and there's no answer back to that," he added.
"It happened to me once when I was 15 and I brought this girl round for Sunday lunch.
"And I was showing off. Then my mum said, 'Simon stop showing off' and I literally couldn't think of a reply."
Simon Cowell jokes that he still relives that day regularly but he now uses the phrase to his own advantage.
"I hated her so much," he said. "And it stuck with me. It's a really good thing to say to the other judges."
Cowell is back on the X Factor judging panel for the first time in four years.
The 54-year-old hopes his return alongside Cheryl, Louis Walsh and Mel B will help make the singing contest the force it once was.
In recent years, X Factor has fallen behind in the ratings fight with its main rival Strictly Come Dancing with more people now watching the BBC One ballroom dance show.
You can hear Nick Grimshaw's interview with Simon Cowell on the Radio 1 Breakfast show on Friday from 6:30 BST.
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A 90-year-old former teacher who is already in jail for child sex offences has had two years added to his sentence after four more victims came forward.
[NEXT_CONCEPT]
Cheryl, Louis Walsh or Mel B can't manage it but there is one person who can put Simon Cowell in his place - Julie, his mum.