CSX2000 Rear End

[Harpoon PV2]

Does any one know the Rear end gear ratio on CSX2000? I ask, because I have been rereading all my Cobra material collected over almost 50 years and reading the great little Brooklands book, Cobras And Replicas 1962-1983, which is comprised of different test articles from the period. In the September 1966 issue of Motor Trend, they tested one of the first 427s and got a 1/4 mile time of 13.8 seconds. That sounded real familiar, so I went back to the first test in that book September 1962 Road and Track where they tested CSX2000, you guised it 13.8. The 427 had a rear end ratio of 3.54:1. No mater how you tune a 260 engine, it can not put out the power of a 427 rated at 425hp and 480lbs-ft, it had to be in the rear end! Make sense, if you could pin a potential customer or a journalist to the seat, it would sell great! The second article, which should be the first, since May comes before September, written by the Godfather of the Cobra, John Christy had no times for CSX2000. Fun side note, the 428 tested in 1967 by Car & Driver turned a 12.2 1/4 mile! It had a 3.31:1 rear end, 390 bhp and 475 lbs-ft.

[grybrd123]

I thought CSX 2000-2069 had 3.54 rear ends, and after that 3.77?

[nkb]

Originally Posted by grybrd123

I thought CSX 2000-2069 had 3.54 rear ends, and after that 3.77?

That's what the World Registry says.

[Harpoon PV2]

Remember, I'm talking strictly CSX2000, which seems to be the only as tested small block to turn in a 13.8 1/4 mile! Unfortunately, I can't find another road test of a 260 in 1962-63. seems they went from CSX2000, straight to the 289 powered cars! I am sure no one is going to dive into the rear end, but would be fun to see if there were some drag race gearing?

[Harpoon PV2]

I just realized, if the rear gears were swapped, It would have been at Dean Moon's shop. Are any of his workers still around from back then?

[rms427]

Quarter mile times for original cobras depend mainly on tires. The original blue dots had little traction so more HP didn't help much. My 1966 Cobra with a 428 turned 12.4 at 112 in the quarter with rain racing tires. I think current radial street tires have as much or better traction.

[Harpoon PV2]

I remember back in the early 80s. one of the magazines tested an ERA with a 427 side oiler Ford top loader, and all the 60s specs, but with BF Goodrich tires. They pretty quickly destroyed the clutch! Cheers, Dennis

[eschaider]

Magazine editors, back in the day (probably today too), manufactured performance numbers that fit what they were trying to sell, usually more magazines and advertising space. The only thing you can say with absolute certainty about reported vehicle performance was that it was what that particular editor wanted it to be — which had no relationship to the real world.

And yes, just like today, a light car with small tires that have diminutive contact patches for the tries to apply all that power to the ground, will smoke the tires. The car's performance was, and is traction limited — if it was really tested at all. More likely than not, it was just a magazine editor's wet dream after driving one of these cars and using up a lot of tire rubber in burnouts and donuts.

[strictlypersonl]

Originally Posted by Harpoon PV2

I remember back in the early 80s. one of the magazines tested an ERA with a 427 side oiler Ford top loader, and all the 60s specs, but with BF Goodrich tires. They pretty quickly destroyed the clutch! Cheers, Dennis

The reason for that was a too-small hose from the clutch master to the slave. It prevented a fast release, and caused clutch slip when power-shifted. Car and Driver was brutal to their test cars.
We quickly changed the supplied hose from -3 to -4 size. No more problems.