Marlborough's players had to take time off work for the game and walked to the ground from their hotel.
Their feat will not be repeated, not because little unions don't have a chance of claiming the Ranfurly Shield, but because Marlborough exist essentially as a sub-union of Tasman, which was formed in 2006 with Nelson Bays.
Members of Marlborough's victorious Ranfurly Shield side will gather this weekend for a reunion to mark their famous win, and the union will also celebrate its 125th anniversary.
Brian Dwyer was a blindside flanker who played more than 100 games for Marlborough and is now one of only seven environmental court judges in New Zealand. He holds fond memories of the day the little guys from Blenheim knocked over a Canterbury side stacked with current, future or former All Blacks, including Fergie McCormick, Tane Norton and Alex Wyllie.
"It's amazing to think how quickly 40 years has gone," he said.
During a tight first half which ended 6-6, Dwyer was partly responsible for a try-saving tackle on Canterbury captain Wyllie.
"I think if Canterbury had scored then they would have had their noses in front at halftime, that might well have made a big difference," Dwyer recalled.
When Brian Ford scampered down the left touchline for a great solo try with seven minutes left, the Shield was secured.
An estimated 3000 travelling fans were among the 15,000 at Lancaster Park and they swarmed the field on the final whistle.
Under coaches Doug Saul and Ralph Caulton Marlborough defended the Shield stoutly as they repelled five challenges.
They eventually coughed it up, somewhat surprisingly, to South Canterbury 18-6 in their second defence in 1974.
"We used to get very good crowds," Dwyer said.
"I think the official record crowd was something like 14,000 - the day we played Nelson for the Ranfurly Shield. I'm not sure who did the counting.
"My father was president of the Marlborough Rugby Union at the time so, whether he was enthusiastic in his counting I don't know, but I don't think they've ever got 14,000 [at Landsdowne Park] again."
Lock Ramon Sutherland, whose brother Alan was also in the Shield team, holds the all-time appearance record for Marlborough with 177 caps, including 135 on the trot.
"At the time it was something quite unique for a small union to win it and it's something we didn't really expect," Sutherland said.
Former All Black coach Sir Fred Allen played his part after he took the team for a training session the Sunday before the Shield game following a 39-3 win over Buller on July 21. He then gave the Marlborough players a pre-recorded speech to listen to before they ran on to Lancaster Park.
"I definitely think it had a great effect," Sutherland said. "Especially for a bloke of his stature as a coach."
Marlborough still play as a stand-alone side when they contest the Seddon Shield against Nelson Bays, West Coast and Buller in the annual four-way tournament but play about only six games a year, which means Sutherland's appearance record isn't under threat.
Tasman meet Canterbury at Landsdowne Park tomorrow and Dwyer said, given the history surrounding the celebrations, the hometown boys might give the defending ITM Cup champions a good run.
Dwyer played in 1975 when Marlborough beat Canterbury 41-17 on the same ground, which at the time was Canterbury's biggest defeat.
The Tasman faithful wouldn't mind a similar scoreline tomorrow.
