The 52-year-old Peterborough Regional College lecturer becomes the fifth person, and the second former councillor, to be convicted of electoral fraud for interfering with votes in the city's Central ward.
Earlier this year, Mohammed Choudhary, who became Peterborough's first Asian mayor in 1997, was jailed for nine months after he was found guilty of forgery.
Jurors have yet to reach a verdict on Razaq's co-defendant and ex-mayor of Peterborough Raja Akhtar, who denies similar charges.
Razaq's crimes were uncovered after voters in the Central ward complained they had been turned away from polls in June 2004 because their ballots had already been cast by post.
A huge police operation, which was to last four years and cost an estimated £1 million, found the father-of-four's handwriting on 39 applications for postal and proxy votes.
Prosecutors at King's Lynn Crown Court said Razaq had systematically hijacked voters' poll cards.
Jurors were told he filled in the cards so that postal votes would be sent not to the electors themselves, but to the addresses of his own friends and relatives, setting up a fraudulent "production line" to sway the ballot in his favour.
Among his victims were husband and wife Jaswinder Kaur and Gopal Singh, of Russell Street, Peterborough, who denied giving Razaq the authority to fill in their poll cards.
The court also heard from couples Sadhia Yaqub and Parvaiz Akhtar, and Sameem and Nadeem Dar, all of Gladstone Street, who said they had never heard of the addresses where their ballot papers were sent.
Razaq never denied it was his handwriting on the poll cards, but his defence counsel insisted he was merely trying to help people get involved with the electoral process.
Mohammed Latif, defending, said: "The poll cards were brought back to (Razaq) by canvassers or, in other cases, he saw the voters himself.
"He filled in the addresses and gave (the cards) back to the canvassers to be signed by the voters. If that is all that happened, he has done nothing wrong; there is no forgery."
The jury, however, disagreed and found Razaq guilty on six out of eight counts of forgery after nearly 20 hours of deliberation over four days.
Four of the convictions were unanimous verdicts while the remaining two were by majorities of 10 to two. He was cleared of two further forgery charges.
Razaq, of Newark Avenue, Peterborough, showed no emotion as the guilty verdicts were read out.
Judge Alasdair Darroch told him he would almost certainly be sent to prison when he returned to court for sentencing at a later date.
He said: "I have to give you this very clear warning: these sorts of offences almost always result in a custodial sentence."