Last year, we had a chance to speak with Chuck Cantwell, the chief engineer behind the 1960s Shelby GT350R. Cantwell was hired by Carroll Shelby himself; he worked as a project engineer in Los Angeles during the Shelby marque's golden years and was responsible for both street and race GT350s, among other things. Cantwell also oversaw performance and prototype testing for the Shelby Mustang—he worked directly with legendary Shelby drivers like Ken Miles, he did duty as a GT350R test driver, and he raced prototypes with the SCCA early in the car's development.
Over an hour-long phone call, Cantwell discussed everything from the GT350's gestation to how Carroll himself "didn't want to" take on the Mustang. An excerpt is below.
Chuck Cantwell: I did a lot of test driving with the car. We tested all the [R-models on the track] before we sold them. The first car was run by [legendary Shelby test and racing driver] Ken Miles down at Green Valley, and then [racing driver] Jerry Titus ran at Pomona ... Occasion came to run it at Willow Springs because there wasn't a very big field. I was just sort of there to fill the field. But it was convenient because we had a car and I'd driven it a lot so ... I ended up running it there, and I ended up winning the race on Sunday. That didn't match our purpose, but it gave me an opportunity to drive again!
You know, I'd driven MGs and stuff like that before. Some modified cars, mostly smaller cars. [The GT350R] was a bigger car to drive, and it felt bigger. But it was a very controllable car. It only had at that time, about 340 or 350 hp, something like that. Now the same engine [when people build them today] has a couple hundred more horsepower. But it was a pretty nice car to drive, actually.
I had learned the track at Willow Springs by riding with Ken Miles. And normally that isn't a very comfortable experience, but it was the only opportunity I had to learn the track and everything, so I took it. So I did learn track rules pretty quickly that way. And I got to drive, and he let me drive some in testing. And then they got busy in other stuff and so I ended up taking over the testing.
On the GT350 and GT350R's gestation, and the Ford connection:
CC: There had been some Falcons run; they didn't make great platforms, and there were some Rally Mustangs at the very beginning. So Ford had done a little bit of development and testing and had some ideas about what to do. I mean, one of the very early Mustang prototypes had been taken out to Waterford [Hills, a track in suburban Detroit] and a couple of guys had run it out there. They had some ideas about what the car needed to make it handle.
Some of these things were pretty well handed over when cars started. And Miles ran, I don't know how long or what period, but he had two Mustang notchbacks that Ford had sent out [to California]. And I think they pretty much had the traction bars and the big roll bar [used on production GT350s] and stuff like that already. And so they tested them and decided that it would be a decent car.
On dialing the car in:
CC: When I got involved, the configuration was sort of pretty much decided upon. And, you know, the street car had to have enough of those components on it that it could be easily made into a race car. That was negotiated with the SCCA, so the street car was three-quarters race car at the beginning. And we did development testing on it after we got the first car together, but it was just a matter of ... the configurations all worked, there wasn't much to do to test one except to dial in the car. It didn't present many horrible problems we had to solve—it was just a matter of getting the chassis settings right and deciding which tires to use. It wasn't terribly rigorous. We started with a very solid platform, and it was just a matter of doing the adjusting.
There wasn't much choice in tires at that time. We used the stock-car tire. And when Goodyear came out with another tire, I tested that out at Willow, and it was immediately worth 2.5 seconds or something on the track. But we didn't have that tire in the first year.
On the GT350's reason for being:
CC: That was the idea doing the car: To beat the Corvettes and the [SCCA's B-Production class], and we were able to do that, and it was very satisfying to do that. Jerry was a pretty aggressive driver. And once we had experienced the competition on the west coast, it was only really two cars: the Sunbeam Tiger of Jim Adams, and Merle Brennan's Jaguar. The Jaguar was hanging in there for a while, but Adams was really more competition I think. And that was probably by far the best Tiger in the country.
When we went to the runoffs, the only car that was faster than ours and we were, you know, we weren't confident in beating, was [future Trans-Am, Indy, and Can-Am champ] Mark Donohue's [GT350]. Mark had done a special engine for it that was really far out and had more horsepower than we had. They had known that was the main thing, the horsepower. Mark had big huge tires on the back, which eventually caused him problems, but he had the fastest car. But that was a GT350 too, of course. So we didn't feel we were going to lose the Runoffs.
On the fact that original GT350Rs are now million-dollar cars:
CC: Well, it's, it's crazy. I mean, I don't know what to say about that. I was at the auction a couple years ago, I guess it was at Monterey, when one from Chicago [Jack Loftus's GT350R] sold. I gave a little pitch for the car at Gooding, and it went for $900,000. Nine hundred thousand plus another $90,000 in commission or so, that's almost a million dollars. And that just seems to be ... I know that GT350 number 002, the first car, went for that in unrestored condition.
When we started—it didn't last for long, because Miles went out in January, I guess it was, or maybe early February, at Green Valley [Raceway] and won the first race he ran. From that point on we had respect, but for a while there, we were the poor sisters [at Shelby's shop], sort of working in the corners of the shop . . . once we won a couple of races, we were considered equals, I guess. Or semi-equals. I don't know about the Cobras, and you know they were running the Cobra coupes then and that kind of stuff.