The Scot, who has a rare match set of Commonwealth gold, silver, and bronze medals, had hoped to run the marathon at the 1964 Olympics, but a knee injury forced him out of the trial, and he was named as non-travelling reserve.
"So four days before the Rome Olympic marathon, I had a shot at the closest I could get to a marathon," Alder recalled last week. "I covered 37,994 metres in two hours - almost 23 and three-quarter miles. The world marathon best then was 2hr 13min 45sec, by Basil Heatley in the Polytechnic Marathon."
Alder would have had 13min 45sec to run less than the two and half miles remaining to be inside the existing world marathon best. "That's not to say I'd have won the Olympics [Abebe Bikila broke Heatley's mark, taking gold] but I'd have been right in contention. It proved I was in superb form at the right time. Unfortunately, at the wrong venue."
Remarkably, Alder's time in 1964 is still the world best - the longest-standing of all world records.
We spoke last week on the 42nd anniversary of another of his great feats. He set Scottish records at 15,000 metres, 11 miles, 12 miles and the one-hour run at Meadowbank (on August 21, 1971).
Alder, who worked as a bricklayer, recalled the two-hour record. "Afterwards, when I went into the shower, I cried. It was galling. I realised I should have been in Tokyo. It was not the selectors' fault. I wasn't stabbed in the back. I foolishly ran a steeplechase for my club, Morpeth Harriers, in a league match and smashed my knee against the water-jump barrier. I missed a fortnight's training, then had to drop out of the trial."
Alder twice set world records at 30,000m, won European marathon bronze, missed the world best at 20k by 12 seconds and at 25,000m by two when officials failed to alert him that he was on schedule, and then the British 10k record by 0.6 of a second in a race he won by more than 200 metres. The Scottish native record he set to claim Commonwealth silver behind Ron Hill in Edinburgh 43 years ago last month remains unbeaten.
Alder laments the fact that UK endurance runners do not do the range of events, or volume, of his generation. "I think that's why the UK endurance depth has declined." Mo Farah being a notable exception eloquently makes his point.
"Cross-country is the manure in the garden for the roses in the summer. I used to meet the same top runners at the English cross-country championships, AAA 10k, and Poly marathon - the same guys. And none of us had a coach. We all had full-time jobs, and families. And no lottery support."
Alder's 400m best was a modest 57.1 seconds, which he overcame by sheer graft. "Some people can be world class on 70 or 80 miles a week. It took 100-plus to get me to international level at 22, and 140-plus to get up to world level. If I'd stayed on 70-80, I'd have been county standard, and maybe a Scottish cross-country internationalist, way down the team."
In 1966 at the Commonwealth Games in Jamaica, even Scottish officials underestimated him. "I cried when team coach John Anderson and athletics boss Rab Forman said I could not run the 10,000. They said it would spoil my marathon chances."
High jumper Crawford Fairbrother and sprinter Menzies Campbell interceded. Alder did not turn up on the team bus, went clandestinely by taxi, pinned on his number and warmed up outside the stadium, then jumped on to the start line just before the gun. Officials only grudgingly acknowledged his bronze. "They said I had better not let them down in the marathon - no pressure, then."
He was in the lead approaching the stadium, but was misdirected. By the time he got back on course, England's Bill Adcocks was 50 yards in front with just a lap to go. Alder caught him in the home straight, becoming Scotland's third Commonwealth marathon champion, after Dunky Wright (1930) and Joe McGhee (1954). It was Wright who had directed him back on course into the Kingston stadium.
"A married women, in them days, didn't get dole. I lost a month's wages in Jamaica. My son, Ian, was eight months old. There was no social security, no income support, no grants - nothing. But there was a newspaper headline: 'Gold medallist broke'. I was getting postal orders from pensioners in Cornwall, but I didn't want charity. I was prepared to lose a month's wages.
"They don't know they are born now. They often want sponsorship when they have achieved nothing. We were not funded, yet were running faster than guys today. I ran to work in the morning, wheeled concrete, got a bus and a plane to London in the afternoon, and finished 16 seconds outside the world six-mile record at night.
"Envious? Yes. Jealous? No. Did it harm me? No, it didn't."
His athletics love affair continues with coaching, but he has been ordered to stop running. "I got a blood clot on my lung three months ago, so I am on warfarin, to thin my blood. They say if it happens again, and goes to my brain, I'll be dead. It was 4-1 against having another blood clot if I stopped the tablets. I don't fancy those odds. Besides, it wasn't Jimmy Alder out there any more. I was running so slowly I got stopped by the police and was told I was kerb-crawling. It wasn't proper running any more. So I have stopped."
Former proteges include some 30 internationalists, but the one with perhaps the greatest potential got away - an elegant, stylish miler who had played county rugby and was on Sheffield Wednesday's books - Neil Black, now head of performance at UK Athletics. He ran 4:02 for the mile just after his 18th birthday. His father had been first reserve for Newcastle United when they won the FA Cup in 1952. In 1978, when Steve Cram made England's Commonwealth team for Edmonton, teenage Geordie contemporary Black beat him in a mile race on his home track at Jarrow. But Black could never shake off injury, perhaps influencing his choice of a physiotherapy career.
"Neil left me - and he was not the last - saying my training wasn't structured enough." Alder believes coaching is more art than science. "It's basic. Simple. It's a touchy-feely thing. If you're running tired, I'll throttle back a bit. Then I will push you to your limits. Some people can do 120 miles per week; some can't; some can only do 90. I find out what your limit is, and go to that limit. It's a philosophy, not a structure."
The late national coach, John Le Masurier, once criticised young Alder for not doing weights. "I asked if he'd ever laid 800 bricks a day. I used to run with barrows of cement at work. I still tell my lads not to ease off for local races. Use them as training. They aren't important. Championships are important."
For the world two-hour record, he wore Dunlop Red Flash (lighter than Green Flash) and was given a kit contract by adidas. "I got the cobbler at Stanhope hospital [where Alder worked] to glue an extra sole on, so the shoes would take the pounding. Each shoe weighed over a pound, but when I wore lightweight shoes for racing, I flew. I liked to train heavy and race light. I'd wear a full tracksuit summer and winter, plus a wet suit in winter. I'd run 20 miles every day; when I dropped down to 100 a week in spring, it was a piece of cake. With a full tracksuit my gear weighed eight pounds. When it all came off, it lengthened my stride."
Alder has also had to go the extra mile in life. "I went bankrupt 18 years ago - lost my business, pension, my house, and my car at 55. I had to start again."
He had to leave Morpeth and the house he had built himself. A competitor from a rival club worked in a building society and arranged a small mortgage. Alder upgraded an old house, ripped out fireplaces, built on a kitchen, rewired, put in a new bathroom. "I am still working in the building trade, but when the next big job is over, I am finished."
Just two British marathon men have gone under 2:17 this year, with four more under 2:20. "I could run 2:20 bouncing on my nose," says Alder. But he has encouragement for the leading Briton: Kilbarchan's Derek Hawkins, who last year clocked 2:14:04. "If you go to a Commonwealth Games and run 2:12 [Alder's 1970 time in Edinburgh was 2:12.04] you won't be far off a medal."
Over the past five editions, 2:12.00 would have won twice and taken a medal in the other three.
"There are men and women who run fast times, and others who run well in championships. Are you remembered for the money you make? Or the championships you win?"
Jim Alder has no doubts.