I hear these lifting theories all the time. I used to hear this kind of stuff back in the early 70's, "Oh, its fiberglass, I'd be to scared I'd get into a wreck because the car will shatter!" I think this myth has now been replaced by the lifting theory.

One of the biggest factors causing lifting is the front end sitting too high. I do see many cars set up this way. Perhaps springs have been changed with the wrong ones. A lot of old BB cars were changed out to small blocks without changing the suspension causing them to ride high.

The little stock spoiler does keep a lot of air from getting under the car causing drag and building pressure underneath, if it is missing, especially if sitting too high in front, this will worsen the problem.

Many, many C3's have very tired suspension joints and bushings which are now sloppy. This gives the impression of the car being light in front when it starts to dance around. The cars did not feel this way when new! 150mph is one heck of a wind. Such forces buffeting a car with sloppy suspension and steering is asking for it.

I posted an article on a stock bodied 68 driven by Heinz at LeMans in the early 70's running 212mph on the Mulsanne Straight. A good sized chin spoiler, but no wings. The Owens/Corning Vettes were running at speeds almost as high without wings. Aerodynamically, there are much better designs today, but the C3 shape isn't all that bad.

Chuck

 

"I posted an article on a stock bodied 68 driven by Heinz at LeMans in the early 70's running 212mph on the Mulsanne Straight. A good sized chin spoiler, but no wings. The Owens/Corning Vettes were running at speeds almost as high without wings. Aerodynamically, there are much better designs today, but the C3 shape isn't all that bad."

A 68-73 at least has a lip spoiler on the back end. 74-79 (without pace car spoilers) have zero downforce producing elements back there.

When even makes a ZR rated 245/60/15 tires these days ?

 

My headlights poped up by themselves also. I think it's because I don't have a check valve on the system so the pull on the headlights became great enough to overcome the vacuum which holds the lights down.

dl

 

dman,

The lip spoiler on the rear deck helps a tiny bit, but the lifting most people carry on about is at the front end. More rear down force only makes it worse. Yet, when the later C3's were so underpowered with 165 and 190 net hp engines, real top end speeds were only in dreams anyway. :yesnod

I think I recall a 220hp L82 being tested in Ohio at the Transportation Facility around '77 against a TransAm, duster, and a Chevy 454 Pickup doing about 130 with 3.36 gears. The Duster was within 3-5 mph. The Trans Am was over geared with 2.73 or lower and only did abut 118-120. :yesnod:

Chuck

 

I've had my 74 over 140 and the car felt solid. But the car is completely rebuilt suspension and steering wise from front to back. I am also using 255/50-16 Z rated tires. My biggest fear was getting a ticket!

Also, the speedometer is within 1 mph up to 120, I had the speedo checked out at a shop that tests taxi speedos and odometers. I trap over 110 even at Calgary's altitude (3600 ft), and my speedo matches the time slips every time.

 

got the car up to 120 and ran out of gear. I would have gone faster, it felt solid. :cheers:

 

Y'know we buy these 20-30 year old cars and the first thing we do is take them on the highway to see how it runs at 70-80-90-100MPH, think about it you have no idea what is wrong with the car, whether a wheel is going to fall off or the whole rear end goes a different direction. Please check these cars out good from bumper to bumper before you go fast in them.

That being said I know mine will go 160 if I drive it over a cliff :D

 

Chuck, I remember that article and the Vette did 126 to top the bunch. :cheers:

 

i had my 73 BB to around 140mph...

 

I've had mine up to about 125 one time, but with the 3.70 gears that was pushing it harder than I normally like to. It would suck to break something at that speed and you never know whats gonna break next on these older vettes :yesnod: But don't get me wrong its always fun to wind her up! :cheers:

 

So, you guys were going how fast?



:D

 

I've have my '86 Crown Victoria up to 125, still had throttle left. 3.08 gears and the AOD. Probably would end up topping out due to drag with that thing.

My dad has gotten to 145mph in his '64 down the interstate. I don't know what he has gone on the strip. Best run was 11.54 but I don't know the mph. Should be in the 10s with the 5speed, 6.50 gears, and 14inch slicks though.

 

135mph

 

Mine runs out of gears at about 130.

 

With my old engine and old front end, new tires, I had her up to 120. Then I backed off. I don't think she had much more in her. Her heart was tired and her legs a little weak. When I get all the new stuff sorted out and broken in, I may push harder. I bet she'll handle over 140 easily, assuming the front end lift isn't too bad. :eek:

 

So how do you get a pic doing 100 MPH with no hands on the wheel???

 

I drove with the vette at 145 once clocked by my friend in my 00 stang GT, the only problem I found about driving this fast in my 82 was that the T-tops were making so much noise that I was afraid that they would fly of and hit the stang behind me. Besides that and the "s" rated tires I think there is no problem in going over 160 in my vette!
Paul

 

Two weekends ago at a Nevada open road race 3 people died. two in a viper and one in a C-4 Vette doing 200 mph. They were all local people (To Reno Nevada)

I also worry about every little engine rattle or if I tightented every little steering bolt when ever i drive in the 150-200 mph range.

Like Chuck Harmond said: Vettes went over 210 30+ years ago. I had no problem in a stock bodied 79 driving 175 mph in an 92 mile open road race. Now with everything modified i have my goal set on a verified 200+ mph street legal car.


[Modified by gkull, 9:38 AM 7/2/2002]

 

IMO. When ever someone tells me that they had their car (like a 69 440 road runner or 1975 trans am going 150 mph. I just say Bull poopie. Even stock vettes either don't have the power or they have the wrong gearing

 

I had mine up just over 100 once, felt pretty stable which given the age of the car was reassuring, but I didn't want to push my luck. Road and Track test article on a car with same engine/gears indicates top speed is 128mph.