Having just bought a 67 Camaro RS Convertible in January, I have been now driving with the top down for the summer.

I notice a pretty good chasis shake at about 45-50MPH. Cannot pinpoint front or rear- I have had a complete front end overhaul- all new parts, new tires and new rims. Speed balanced wheels at two different shops, tires zero out on high speed balance. 4 new shocks too. Below and above this speed range no shake. If I drive at 48MPH constant speed-pretty good chasis shake going on.

When I drive with the roof up, the shake is much much less noticable (I realize the roof is adding bracing and suppport)-

My question is for fellow first gen convertible owners, is this just the way it is for this era convertible?

The car has all the cocktail shakers- x brace is in place.

I am going to replace the u-joints and have the driveshaft balanced...not sure what else is to try????

The car has a 327 motor, trans is Powerglide 2 speed, but the rear is from a 69 Camaro 396 and is a 12 bolt posi.

all help and suggestions welcomed...

thanks
JL

That is definitely "NOT the way" of first gen convertibles. Mine is solid as a rock, top up or down, well into triple digits on the speedo.

keep looking, you'll find that shake.

Hoping that others can suggest solutions based on their experinces...given the symptoms...

If you are familiar with old school tire/wheel balancing, then I would find someone with the old style equipment and get it done. This is the kind that spins the tire wheel combo up while it is on the vehicle. Also another big thing to check is that the hub and drum assembly are balanced. Convs are extremely bad for amplifing vibration. My bet is that you will find it on a hub and or drum assembly.

How do you check the balance of the hub and drum assembly?

If it were that, wouldn't the car have the shake at many speed ranges and get worse when going faster, not go away like it does?

thanks
JL

Good points above. I will say, however, that I have some cowl shake in some cirumstances even with an 8-pt rollbar, welded SFC's, solid body mounts, shakers, new floors....

I agree with JimM, my 67 convert. is very tight, no vibrations or shaking at all, at any speed, top up or down, still having the original suspension. At about 60mph and up, the front end "wanders" a bit, but I will be putting on a new front end kit and sway bars over the winter, which hopefully will rectify the wandering. It really sounds like the tires or hub/drums are out of balance.

If it is just one speed range it probably is ballance, My experiance with a vibration was when I replaced the yolk on the pinion gear just to get rid of a small leak it vibrated bad ( the hole car ) seemed from the back but? I spun the drive shaft 180* and it was gone. I still have what I think is washboard roads seem to really pronounce the convertable flex, My suspitions are the gas shocks are firm enough to cause it on those roads. Around 70 and up.
I may try O.E. shocks and do an expencive test.You will have to do your own best guess on vibrations they can really be tuff.

in suspension thread I just resolved a 65mph vibration in my 69 coupe. Loose upper ball joint bolts that nobody has ever spotted before. New ball joint and retorqed the other side and for first time I can cruise 70mph without losing my teeth fillings. Double check all those suspension parts and bolts. :)

put the rear of the car on jack stands, secure the car with straps and put in gear and slowly bring the car to speed. see if it still has the vibration. be careful in case it falls off of the stands.