Speculating on the past...

[Steve Cassani]

During Sebring, 1964, Shelby arranged for the Hurlock brothers, then the owners of AC Cars, to meet with Klaus Arnig of Ford Motor Company. The purpose of the meeting was to introduce Arnig and Shelby's ideas for the next generation Cobra, what we would appreciate today to be the 427 engined car.

At this point I want to step away from the historic record and offer a few thoughts of my own. Those who are famliar with the design of the Shelby/AC 427 car have come to accept that the frame was not equal to the stress induced by the suspension and the torque of the big V8. The frame tubes were constructed of too thin a steel and the tubes themselves should have been further apart. How this came about, given Arnig's experience in chassis and suspoension design, remains a puzzle until you consider the manufacturing limitaitons AC brought to the design.

My guess is that Arnig did not have a clean sheet of paper, or anything close to it. The current contract between Shelby, Ford and AC defined the range of design practices Arnig could call on to satisfy the needs of the second generation car. AC was still far from financially healthy and I doubt they had the option to initiate new procurements from their suppliers. So the basic design parameters that had shaped production of the 289-engined cars still held when Arnig was assigned the 'new' design.

Remember that the meeting between Shelby, Arnig and the owners of AC occurred while the Daytona Coupes were competing, with faster lap times and, more importantly, faster cornering speeds than had been attained with the roadsters. The modifications to the original 289 Cobra chassis, including Pete Brock's idea of a 'cradle' to lower the engine within the chassis, were being shown to be correct. And yet the geometry of the 427 design more closely approximates the original roadster chassis. None of the improvements Shelby's engineers made to the 289 chassis found their way to the big-engined, Mk II car.

One could argue here that the new chassis was improved to include the advantages of the modifications made to the original without having to repeat the changes themselves. I doubt it. The centers of gravity in the 289 and 427 chassis are very close, too close I believe to support the idea that the new, big-engined chassis was up to date so far as what competition had shown to be definite weaknesses in the original. I don't want to say the Mk II chassis mimics the original. Obviously it doesn't. But it does carry over as much of the older, pre-V8 design from the Ace as Arnig had to accept, given the financial and physical limitations of what was at the time part of a cottage industry in Britain. Ac could not have produced the car Arnig was capable of designing or, to put the point another way, Arnig had no choice but to shape his design within the manufacturing capabilities of AC.

Before you grab the keyboard in an herioic defense of the car, the people or any of the subjects I have defamed, give a thought to this: Notice the repetitive designs that came from AC in the later sixties and early seveties. Even the Frua-bodied, 428 car used the frame and suspension of the 427 Cobra. AC simply could not implement a new design. And this isn't lack of imagination or typical British stodginess; a small company doesn't have the surplus resources to both build cars and support starting from scratch with a new design.

[HIQ]

OK.....Are you expecting an arguement?

[mr bruce]

The tortional twist of the 289 frame was taken care of by the backbone around the engine/trans in the Daytona Coupes. I would say the coupe frames were way ahead on that point, vrs the 427 frame, even with it's 4" tubes. (just look at the wrinkles in the bodys, in front of the doors on vintage pics, on the 427 models.)As for the suspension layout, the constant variable rollcenters of the leafspring cars amaze me to have won the world championship.Then again, the greatest drivers of the day were hired by Shelby to pilot the cars. I would like to see where the "extra" 3" of wheelbase was supposed to be in the Ford designed frame/suspension were inserted.

[BMK]

Makes good reading. Thanks guys

bernie

About to go out and twist some chassis in the sun!!

[Cal Metal]

I think the major issued that needs to be addressed is that the 427 Mk II chassis was doomed with inherent compromises due to the fact that it would have been very difficult for Ford to perform a major redo of the Cobra given the incredibly low production numbers that were generated by the 289 cars.

For example, Duntov at Chevrolet, in getting the swing axle rear end for the '63 Corvette, had to settle for the use of '55-'64 passenger car components for his front end. This is when the '63 Sting Ray was producing over 400 units per week (20,000 units annually for five years). Contrast that with a 3-4 year TOTAL production run of 630+ cars with the Cobra. If GM couldn't achieve scale with that number (in allowing Duntov to build an entirely different front end), Ford would have been out of their minds in throwing any serious $$$ at a revamped Cobra project that produced almost zero cars by comparison.

Just a financial perspective.

[Excaliber]

Looking at it from a financial point of view it's amazing Ford offered ANY money to the program.

Seems to me it was more about "beating" the competition than making a profit. Or perhpas it WAS about making a profit through "good press"?

Ernie

[What'saCobra?]

Perhaps you have seen a copy of the letter from Duntov to the more senior management at Chevy written in either 54 or 55?

He made a comparison with the easy availability of FORD engines, factory performance parts, factory help, big aftermarket support by specialist vendors to encourage Chevy to get with the program, like FORD, get their collective heads out of the sand and encourage use of their engines. Which letter certainly worked, in spades, when you look at the huge availability of cheaper unit priced pieces from GM today.

Jim Hall certainly benefited from Duntov's thinking and encouragement, as did many others.

But, FORD was first with the mostest, particularly with the thin-walled 225/260/289/302/35, which seriously benefited the thin-skinned CS at the time. Ha! Just to raise the B.P.!