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Old 03-29-2005, 01:07 PM
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David Kirkham David Kirkham is offline
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Join Date: Mar 2001
Location: Provo, Ut
Cobra Make, Engine: Kirkham, 427
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Pat,

I meant to say "aluminum steering column tube." Our steering shafts are stainless steel. Sorry for any confusion.

Interestingly, Borgeson offers an aluminum u-joint assembly for the steering system and they don't seem to have a problem with it.

I have thought many, many times about using an aluminum shaft, but I have never done it. Actually, the forces on the shaft are really quite small, (think about how little force you can apply--even in a panic--on the steering wheel). I think it is interesting we are perfectly happy with aluminum, and magnesium wheels, uprights and other parts, but everyone gets squeamish (myself included) about aluminum steering shafts. One day I will do the math and figure it out.

Turk,

I agree the weight differences would be easier to understand if we were able to weigh cars with identical set ups. Unfortunately, I don't have any CSX4000 cars here with an aluminum block, heads, flywheel, and water pump to weigh. I wish I did and then I would post that number along side the rest. That is why I was careful to note exactly which cars had what parts so everyone could see the differences.

I would not dismiss weight differences between cars that are not identical because we can measure the exact differences of the weight of the different components and calculate the difference. For instance, a block is about 40 pounds lighter, and the heads are about 40 pounds lighter, and the flywheel is about 10 pounds lighter—for approximately 100 pounds of the weight difference.

Regardless, an iron motor is not 300 pounds heavier than a complete aluminum motor--so there is a very significant weight loss somewhere.

Finally, my comments were very much directed at comparing an original car to what can be achieved on our cars today. There is a very real 300 pound weight difference between our cars with all of the lightweight components, (block, heads, flywheel, water pump included), and an original 427 Cobra. My comments were mostly directed toward the quiet congregation across the pond who have claimed we are dumb for years. It seems Trevor and Gerry may have been right—a car the weight of an original small block DOES handle better than an original iron engined 427 Cobra. I believe the aluminum 427 cars with all of the lightweight parts are now in that envious company the English have been talking about for years. The aluminum engined 427 cars now have the best of both worlds—great power and great handling.

I believe they are correct as I have now had a chance to drive cars of very similar weights and compared their handling characteristics—an original 427 Cobra with an iron engine, a Kirkham 427 with all of the lightweight parts, and a Kirkham small block with all of the lightweight parts. Of course, the weight thing can be taken to extremes and therefore, I prefer the Kirkham Small block for its outstanding handling—and the Kirkham aluminum 427 car is pretty darn great! I overall prefer the Kirkham 427 for its combination of light weight and power, and I finally, prefer the original 427 because it is the coolest car in the whole world.

So one car is not really superior to another—they just fill different needs of different customers.

David
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David Kirkham, President Kirkham Motorsports
Manufacturer Aluminum Body Kit Cars and supplier to Shelby* for their CSX4000, CSX7000, and CSX8000 289 and 427 Cobra
*Kirkham Motorsports is not affiliated with Ford or Carroll Shelby or any of their trademarks.
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