He and Cleckler landed separately on the island of Iwo Jima, two farm boys from deep South Texas separated by confusion and mortar fire.
Block was killed, but not before achieving immortality of sorts as one of the six men photographed raising a U.S. flag in what became an iconic image of American valor.
The photo by Joe Rosenthal inspired the bronze sculpture next to Arlington National Cemetery. The plaster model for the sculpture was brought to the Marine Military Academy in Harlingen in 1982, and Block's body was reinterred there for the 50th anniversary of the battle in 1995.
Cleckler always wore the ring Block had handed him in February 1945. He visited Block's mother in Weslaco that April, and she asked him to keep it. It stayed on his finger through his military police and color guard duties at Corpus Christi Naval Air Station, his football career with the Bobcats at Southwest State Teachers College in San Marcos, and his years as a Harlingen teacher, coach, high school principal, husband and father.
But on Thursday, Cleckler, now 86, said it was time to pass it on. He is the last of his cohort of eight high school students who graduated early to go to war, he said, and when he joins other local veterans for coffee, he's one of only two remaining who served in World War II.
Some of his "kids," as he calls former students, are passing middle age. He thinks sometimes his memory slips, though a word can quickly nudge him back to one of his many stories.
In a small ceremony in front of Block's grave marker, Cleckler handed the ring to Brig. Gen. Stephen Cheney, U.S. Marine Corps (Ret.), the academy's president. It will be displayed at the school's Iwo Jima Memorial Museum, which draws about 10,000 visitors a year.
"I had second thoughts, until I think about how old I am," he said after the ceremony. "There's not many World War II vets that you can sit down and talk to any more. . . . All my buddies are gone. My kids all grew up."
It's a reluctant separation, Cleckler said.
"That ring could tell a long story," he said. "It has quite a lot of mileage on it, even after it came back to the States."
Cleckler is tall and animated, not at all shy about recounting the tale that started with a trio of teenage boys playing hooky during their senior year of high school. Block had a pickup full of gas and convinced the others they had no excuse to waste the day. They'd go see a show.
But the theater manager in Weslaco was a football fan who would surely tell on them, and when they drove to Mercedes, they didn't like the movie. Cleckler can't recall what they saw in Harlingen, some 15 miles east, but he well remembers how the Marine recruitment office next door seemed the answer to the next morning's woes.
Sure enough, when the principal asked them the next day to explain their absence, they had an alibi. All carried Marine recruitment pamphlets in their pockets.
"He said, 'Well, I misjudged you boys. When are you leaving?"' Cleckler said.
Next thing they knew, they were heading to boot camp with other boys who had heard the military could give them an early out from high school.
Block purchased the ring at a PX in 1943. He had already seen combat when he bumped into Cleckler while on liberty in Hawaii, and said he had a bad feeling about the next campaign.
"I told him to go jump in the lake," Cleckler remembered. "But he got that look in his face. I saw that he was serious. A lot of guys got that feeling."