From the outset, the Chaparral's pace wasn't in doubt – the car set a new track record by some nine seconds in qualifying, a full 12 seconds up on the fastest Ferrari. Still, the question being asked was whether the automatic gearbox could sustain itself over a 12-hour race on the rough, tough circuit. 

“You always have worries – they're prototype vehicles!” he says. “But we'd gained really good experience by then. We'd had a boot problem, but we thought we had it fixed and, as long as you kept the axles properly greased, we felt we were OK. The torque converter had a bit of a cushion in the drive train – it's not as firm as a racing-tight clutch – so we felt it was a bit of an advantage, in fact.”

Come the race itself, things ran as normal until the early evening. Then, from temperatures reported at 95 degrees Fahrenheit ambient and 130 degrees track at the start of the race, the clouds began to bubble up and the record heat was soon superseded by a massive, Floridian-style downpour around 5:30 p.m.

“We didn't anticipate the rain, of course,” says Hall, “so we weren't totally prepared for that, but we did make some good decisions during the race and it all worked out.”

One potential problem they faced was that the Chevrolet engine wasn't immune to the water. With the 327's uncovered air inlets pointing straight out of the bodywork, the risk was that too much water could enter the engine if the pace was too slow.

“Certainly it could happen and there wasn't really much we could do about it,” Hall admits. “As long as the car's running and it's just raining in there, it'll absorb and evaporate that measure of water, but if you got a big dump of it in there somehow, you could certainly flood out the engine.

“Our major concern was that we wouldn't be able to restart out on the circuit, so we took some precautionary measures to try and make sure we didn't get caught out there where we couldn't get going, because you can't push-start those cars because of the automatic gearbox.”

As the rain continued to fall, puddles turned to floods, and standing water was everywhere around the 5.2-mile circuit. Some places had water up to three feet deep. One stretch particularly affected was the pit lane, thanks to a lack of drainage due to the concrete wall separating it from the pit straight.

“There was so much water on the circuit that it was coming in through the radiator,” says Hall. “The radiator was right at the bottom of the front of the chassis on that car, so the water was coming through that opening, over the top of the windshield and into the cockpit. We couldn't go very fast through those deep puddles, because I was worried it would blow apart some of the ducting in the radiators, so we went awfully slowly through it.

“We had a tremendous lead built up by then and when I pulled into the pits I told Hap, ‘If you look at the lap times these guys are running' – 10-15 minutes per lap, the rain was so bad – ‘we could probably sit here for an hour and wait this out and still maintain the lead!'  But he got antsy and, although we did stay in quite a while and we went over everything we wanted to go over in the car, he said, ‘If I go out and just do one lap, that's something, so how about it?' I said, ‘Well, OK, but be careful you don't get stalled out there.'”

In dry conditions, the lap times should have been around the low three-minute mark (Hall had set a record of 2m59.3s earlier in the race). But the wet conditions had put Hall's times anywhere from seven to 10 minutes. Sharp's times were largely in the four-to-five minute range, before they dipped below four at nearly 8 p.m. Hall says that the stint Sharp ran in the brutal conditions was one of the keys to the team's success.

“He was kinda ‘Hero of the Day,'” says Hall. “While he was out there it got dark, and when he came in I asked him how many puddles there were and he said there were a few. I said, ‘Well, how would you feel about going out and running another hour?' and his eyes got really big, but then he said, ‘Yeah, it's probably the smart thing to do,' so he got back in and drove another hour and did a great job. Then he brought it in and I did the final stint.

“It was fortunate – we did have some good luck – and we did have to rob a piece off of the other car. We had a voltage regulator that gave up and, in order to make sure we had a good one that had been tested, we just brought the other car in and took its regulator. It was a precautionary move that put the other car back farther than it should have been, but I still think it was the right decision.”

The rain – ever the great equalizer – also brought the classes closer together, as the smaller displacement Standard Triumphs, Austin-Healeys, MGBs and Alfa Romeos in the field could match and pass the slowing, halting bigger cars with relative ease. That was quite the turnaround from the perpetual traffic problems faced by the top cars in the dry, as Hall explains.

“Yeah, that is one of the big challenges of those races, dealing with cars that are way different in performance,” he says. “Some of those guys probably hadn't done much racing, and so they're running around out there and in some places going 100mph slower than you are. Boy, you really had to be awake! Sebring was not so bad for that because – except down at the warehouse part of it – it's wide everywhere, so you've got a lot of room. So, if you're reasonably cautious overtaking, you can always make some kind of correction if the guy does something that you're not expecting. But when it's narrow, and you've got stuff you can hit on both sides, you have to be disciplined enough to think, ‘Hey, maybe the best thing to do is not pass him going into the corner, I'll get him coming out of the corner.'”

The rain coupled with the darkness made visibility an even bigger challenge, despite having the clear field of vision in the open-top Chaparral prototype. Angle and direction was important for the effectiveness of the car's headlights, as Hall explains.

“We redesigned the endurance cars we ran later and moved the headlights up higher,” he says, “because the angle between our headlights and the ground was so small that it spread the light over a big area and you had to point it just exactly right. But whenever the car changed in pitch angle, under acceleration or especially braking, you lost that. So that year we discovered that our headlights were really not very good and we were maybe fortunate that we were running slowly when it got dark.”

Still, with a four-lap lead under them and many of the manufacturer entries long since retired, Hall and Sharp ran the balance of the race cruising toward victory as the track began to dry and return to its normal, non-drenched state. It marked an all-American win at Sebring for the first time since 1953, as a Texan and an Oklahoman brought home their Texas-built, Detroit-powered machine.

The victory also showcased the durability and reliability of the Chaparral, despite the battering that Sebring throws at anybody and everybody.

“That car was first run in the fall races in '63,” says Hall, “and then got developed all season long in '64. All the while, we changed the things that broke and tried to do a better job of putting them together and preventing the problems. And I guess I'd admit, we probably over-designed them, because we didn't want it to be so tough to maintain and it just turned out to be a very reliable car. That chassis was originally designed in '62, and it was probably a little overweight, but it was the first monocoque chassis to go into service, around the same time as the Lotus 25. But (Colin) Chapman's Lotus was aluminum, ours was FRP (fiber-reinforced plastic). So, although it was a little overweight, it was very, very sound, and we used it right up until 1967 with quite a few mods.

“Sebring is certainly tough on a chassis,” he adds. “It was concrete block at that time and didn't fit very good in some places, and there were pretty big dips and so forth, so that the ride is important. That's what we got from our extensive pre-race testing down there: we did setup work on springs and shocks, and certainly the fact that we had to slow down and run in cooler weather was probably a benefit to all cars. But by that time, we had a four-lap lead, so we could have eased off considerably.

“We certainly thought it was worthwhile doing the race, and we felt fortunate to have won it, to tell you the truth. You work your tail off to do these things and often it doesn't work out, so it was a good thing for Chaparral.”

The Sebring win stands today as one of Hall's defining highlights in a racing career that lasted for more than 30 years, including a win in the 1980 Indy 500 with his stunning 2K, and finally came to an end at the close of the 1996 season.

• Fittingly, racer and innovator Hall will be honored by the Road Racing Drivers Club at its “RRDC Evening with Jim Hall” on Thursday, April 12, at the organization's fourth annual West Coast banquet prior to the Toyota Grand Prix of Long Beach. CLICK HERE to find out more.

The 60th Annual Mobil 1 Twelve Hours of Sebring Fueled by Fresh From Florida takes place at Sebring International Raceway, Fla., March 14-17. This year, adding even more luster to this classic event, the race is once again the opening round of a world championship – the 2012 FIA World Endurance Championship.   

Find out more at www.sebringraceway.com

And to purchase tickets, CLICK HERE