'66 Malibu N/SA

[Dave Muller]

Well, I had the Chevelle out to Wild Horse tonight, with mostly good results. I didn't get a good burnout on the first pass, blew off the tires on the launch and shut down at half track and cruised down the rest of the way. Inspecting the car after the run I didn't see any indication that the slicks were hitting anywhere, so I think I managed to get enough clearance.

I took a second pass and got a good burnout. I wasn't even trying to use the 2-step but it hooked and went arrow straight all the way down. I had thought I might shut down at half track again, but it was doing pretty well so I went on to 1000 feet, and then the stripe wasn't that far away, so in the end I ran it out all the way. Here's the result:



That's two tenths under the index on the first pass! Now admittedly I was 12 pounds light, but still... and that was at 1200 feet. No idea about the DA, I was focused on other things and never checked.

Now for the one negative, and why I was considering an early shutdown on that run. There's a significant vibration in the drive line from half track on. Doesn't feel like it's really trying to tear itself up but it's quite noticeable. It gets a little worse on the way down until 60 MPH or so.

My inclination under the circumstances is to go ahead and race it next weekend unless someone convinces me I'll hurt the car running it this way.

[David Lee]

Fantastic!!!

[HP HUNTER]

Excellent results!

[RobbieRacer]

Re balance the Slicks first, I had the same thing happen with new tires on my 67.
It sounds like you had a great first time out. Cool!

[Greg Reimer 7376]

Great job! Balance the tires, see you in Fontana. Fontana's maybe a tenth quicker than WHP, maybe not. Sounds like your initial set up is pretty good to start with.

[Dave Muller]

Originally Posted by Greg Reimer 7376

Great job! Balance the tires, see you in Fontana. Fontana's maybe a tenth quicker than WHP, maybe not. Sounds like your initial set up is pretty good to start with.

I guess it's possible, though I did have them balanced when they were mounted. But it doesn't really feel like tires to me.

[Alan Nyhus]

Well done, Dave.

Make sure to check the fit of the drive shaft yoke into the transmission if it's been fitted with a bushing or roller bearing. -Al

[Mark Yacavone]

Good job on the car, Dave.
I would attempt to fix it before going to Fontana.
Did you have the tires spun balanced? 0-0, while you were standing there?
Who built the driveshaft? .083 wall, 3" ? Should be fine in this application.
Did you bottom it out, then pull back about an inch , for installation?

You have adjustable upper bars? Did you check U-joint angles with a protractor?
This is probably the biggie here.
I don't believe it's the transmission. I check the back half drag many times, by spinning it with a yoke in place .Bent out put would have shown up then.
No extra roller bearings in this trans. It is your basic, entry level model.

[Dave Muller]

Originally Posted by Mark Yacavone

Good job on the car, Dave.
I would attempt to fix it before going to Fontana.
Did you have the tires spun balanced? 0-0, while you were standing there?
Who built the driveshaft? .083 wall, 3" ? Should be fine in this application.
Did you bottom it out, then pull back about an inch , for installation?

You have adjustable upper bars? Did you check U-joint angles with a protractor?
This is probably the biggie here.
I don't believe it's the transmission. I check the back half drag many times, by spinning it with a yoke in place .Bent out put would have shown up then.
No extra roller bearings in this trans. It is your basic, entry level model.

I don't really think it's the trans either, but that was the sensation. Which does lead me to the driveshaft. That was from Arizona Driveshaft & Differential, on Southern near Mesa Ave. I'm pretty certain it was 3". I'll dig through my paperwork. I'll also see how far it can slip into the trans later today. I always had a feeling though that the shaft may be just a little shorter than it should be.

The tires & wheels were static balanced, but I'll have them done again and dynamic this time to be sure. I wasn't watching.

I did set the pinion angle, but I've never done that before and I wouldn't guarantee the work. I used an inclinometer and set the pinion pinion angle parallel to the output shaft, although that left both about 4 degrees off from the driveshaft, as best as I can tell.

[Mark Yacavone]

From my experience , most of these high speed driveline vibrations are shaft related. Usually from not having a 3-4 degree balance between the two angles.

Did you say you still had the mufflers on it?

I would guess it was still almost 90 degrees at 8 pm, and ODA approaching 4000'.

Already been over 100 in the valley.