Selling the bonds would ensure the state would pay $350 million a year for the next 30 years, saving at least $1.5 billion in interest, Manchin said.
Without the bonds, the state's annual pension plan-related debt payments will increase annually, ballooning to $724 million in 2034, according to the governor's office.
Attempting to dispel misconceptions, Manchin said this is not new debt, but debt that has existed for more than 40 years. He also said no burden will fall to taxpayers.
"Not one penny of taxes will be raised," he said.
A couple of weeks ago, West Virginia representatives went to Wall Street to refinance road construction bonds. Four other states, including Hawaii and Texas, were selling bonds that day.
West Virginia's bonds sold faster and at a higher yield than bonds for the other four states combined, Manchin told the crowd.
"Wall Street's looking very favorable on West Virginia," he said.
Refinancing the road bonds saved the state nearly $19 million - more than the projected $13 million, he said.
After the presentation, as he shook hands and signed an autograph for a child, Manchin disputed allegations that selling the bonds is a gamble.
Don Blankenship, Massey Energy Co. chairman and CEO, has paid for advertisements on television and radio arguing that selling the bonds is a gamble.
Blankenship and other opponents warn of the consequences if stocks sour as they did earlier this decade. They also have decried the up to $55 million earmarked for lawyers, bankers and other specialists who would be hired to help the state with the bond deal, according to the Associated Press.
"The biggest gamble is to do nothing," Manchin said after his speech.
Others who joined Manchin on Tuesday were state Auditor Glen Gainer, West Virginia Education Association Executive Director David Haney, West Virginia AFL-CIO President Kenneth Perdue and West Virginia Chamber of Commerce President Steve Roberts.
Perdue said that 300 AFL-CIO delegates unanimously approved a resolution supporting the amendment during a recent meeting, and that the state's 100,000 members have been contacted and urged to vote in favor of the amendment.
Haney said the state's Education Association has 1,700 members from the Eastern Panhandle, and that state revenue should no longer be unnecessarily devoted to paying off the pension plan debt.
A fixed payment plan will allow money to be dedicated to building the best education system possible, he said.