Correct Mid-Year Clutch Cross-shaft??

[Dwight P.]

At recent National and Regional flight judging(1965 SB Coupe), my clutch cross shaft was "dinged" a couple of points for originality. I believe that one of the judges mentioned that my cross-shaft was missing a ridge along the underside of the horizontal piece.(The red grease cap is in place)
My question is this....What are the differences between an original cross-shaft and an after market cross-shaft?

Thanks,

DP

[Joe L.]

Re: Correct Mid-Year Clutch Cross-shaft??

Dwight-----

I have NOS examples of every mid-year clutch cross shaft (there were 3 used over the 63-67 period). None has what I would call a ridge along the underside of the tubular section. Plus, from my observations I don't ever recall seeing such a ridge on any cross shaft. So, I really don't know what they are referring to.

[Wayne M.]

Ditto Joe's comments

My originals (one '63-65 SB type; two '65-66 BB types [one NOS w/GM parts sticker]) have no visible ridge, nor anything detectable by feel.

Am curious to hear if any others have heard of this -- certainly isn't mentioned in the 1965 TIM&JG.

[William C.]

Re: Ditto Joe's comments

Only thing I have even noticed is some differences in the area where the arms are attached to the shaft. Never saw a ridge on the bottom.

[Joe R.]

Re: Correct Mid-Year Clutch Cross-shaft??

Hi Joe:

Could you elaborate on the differences in the 63-67 cross shafts? I have noticed that some shafts have much more pronounced welds on the two arms, and had wondered whether that indicated anything about the vintage. I'm curious to learn what other differences there may be.

[Loren L.]

Name of judge from the sheets? *NM*

[Joe L.]

Re: Correct Mid-Year Clutch Cross-shaft??

Joe-----

The main difference between all of the shafts is the angularity between the 2 levers. Otherwise, they are virtually identical. The welds varied even on arms of the same part number.

[Joe R.]

Re: Correct Mid-Year Clutch Cross-shaft??

Hi Joe:

So if I understand you correctly, GM changed the angularity between the two arms two times (total of three variations) during the 63-67 production run? Do you have any idea why? Was the change significant?

I always thought the cross shafts were the same for 63-67, and possibly well into the C3 era as well.

[Joe L.]

Re: Correct Mid-Year Clutch Cross-shaft??

Joe-----

I do not know why the changes were made, but there were 3 variations. The first one, applicable to 63-66 except big block, had an angularity of about 135 degrees between levers. The second was used for 65-66 with big block. The third was used for all 1967 as well as all 1968-81. I do not yet know the angularity between levers of the latter two.

[Wayne M.]

[John H.]

Re: '65-66 BB clutch X-shaft (angle)

Wayne, I just set up an original '66-'67 shaft (3888279) in the same manner as in your photo, with an inclinometer on the long arm, and it shows 158* angular separation between the short arm and the long arm.

[Joe R.]

Re: '65-66 BB clutch X-shaft (angle)

Hi Wayne:

Here is a photo of a cross shaft that I picked up a while back, thinking that all midyear cross shafts were the same. This one has a smaller angle than the one in your photo. I measure 43 degrees off the horizontal, which calculates to (180-43)= 137 degrees on this one versus 155 degrees on yours.

Also, the center-to-center distance on the arm in the foreground is 4.65 inches, and 4.0 inches for the arm in the back.

Any idea what application this arm would be correct for?

[Joe L.]

Re: '65-66 BB clutch X-shaft (angle)

John and Wayne-----

Great, now it looks like we've got the angle figured out for all 3 of the shafts and I didn't have to go out and find mine to measure. That's what I like---a team effort.

[Joe L.]

Re: '65-66 BB clutch X-shaft (angle)

Joe-----

From the angularity measurement, I'd say it's the 63-66 small block shaft. I measured 135 degrees for that shaft, but it's not an absolutely precise measurement.

[Wayne M.]