General Question
Race Director
Joined: Oct 2005
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From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
Now re-do your math with a 3.36 rear end (which is what the C&D test car had in 1966 when it ran the quarter in 12.8sec) and with 3.08 rear end which was available with the 425/435HP cars. You will find the top end with a 3.36 to be about 155 and its over 170MPH with the 3.08.
Instructor
Joined: Aug 2009
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From: York Pennsylvania
Team Owner
Joined: May 1999
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From: Columbus Ohio
CI 3-4, 8-9-10 Veteran
St. Jude Donor '06-'08-'10
The accuracy of the speedometer also comes into play unless there was timing equipment involved.
Instructor
Joined: Aug 2009
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From: York Pennsylvania
Yes and I agree, but the math matched the tire size, speedo and tach in my fathers case.
Le Mans Master
Joined: Dec 2004
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A few notes here:
1. The standard rear in the 66/67 425/435 HP engines was 3.55, not 3.36. There were different standard rears depending on engine/transmission combination.
2. It was not unusual for solid lifter big blocks to hit 7200 RPM. This is how a 4.11 rear end car could get to 140. A cam, improved valve springs, a three angle valve job, and strengthened con rods (the weak point in stock BBs) can easily allow for 7500RPM utilization.
3. A quick note on areo for the C2. The L88 at LeMans in 1967 was able to hit those speeds without a front spoiler. C2 cars also had better aerodynamics than the follow-on C3s (though the 80-82 series did have markedly better areodynamics than the earlier cars).
1. The standard rear in the 66/67 425/435 HP engines was 3.55, not 3.36. There were different standard rears depending on engine/transmission combination.
2. It was not unusual for solid lifter big blocks to hit 7200 RPM. This is how a 4.11 rear end car could get to 140. A cam, improved valve springs, a three angle valve job, and strengthened con rods (the weak point in stock BBs) can easily allow for 7500RPM utilization.
3. A quick note on areo for the C2. The L88 at LeMans in 1967 was able to hit those speeds without a front spoiler. C2 cars also had better aerodynamics than the follow-on C3s (though the 80-82 series did have markedly better areodynamics than the earlier cars).
Instructor
Joined: Aug 2009
Posts: 193
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From: York Pennsylvania
