66 A arms

[Tony C.]

The long nuts that holds the cross shaft and the shims at the upper A arms are black phosphate or zink the my 1966 Judging Guild dose not say.
Thanks Tony

[Tony S.]

Re: 66 A arms

Black phosphate.

[Gary B.]

66 Upper A-arm nuts; who sells them?

Does anyone know of a source for those thick nuts in black phosphate?

Gary

[Tony C.]

Re: 66 A arms

Gary
I think LongIsland corvette supply has them. I looked in his book and he has the nuts for 64 65 and another for 66 67 in zink. In the Judging Guild reads that 66 has long nuts but I think in 67 thay did not have long nuts. So which one right and what to use.
Tony

[Gary B.]

66 A arms

Tony,

I can tell you that my July build date '66 had long (about double thick) nuts that were almost certainly not zinc originally. I can definitely believe they were black phosphate originally.

Are the ones that LICD sells for '64 & '65 double thick and black phosphate?

Gary

[Tony C.]

Re: 66 A arms

Gary
Yes LICD sells for '64 & '65 double thick black phosphate.
Tony

[Michael H.]

Re: 66 A arms

Tony,

I can tell you that my July build date '66 had long (about double thick) nuts that were almost certainly not zinc originally. I can definitely believe they were black phosphate originally.

Are the ones that LICD sells for '64 & '65 double thick and black phosphate?

Gary

Yup, most 66's used the same tall nut as 63-65. Toward the end of the 66 model year, the self locking zincad plated nuts entered production.

I don't think the original tall nuts for 63-early 66 were black. May have been either natural/unplated or medium grey plated.

[Tony C.]

Re: 66 A arms

How long is the long nut. I have 4 nuts that are 7/16" long is that the right size or are thay longer.
Tony

[Michael H.]

Re: 66 A arms

How long is the long nut. I have 4 nuts that are 7/16" long is that the right size or are thay longer.
Tony

Just tried to get a dimension from the nuts on my 66. Looks like .450" tall, or somewhere very near that. I can get a more accurate measurement tomorrow if necessary.
If yours measured 7/16", that's .4375", or very close to the dimension I posted. Sounds like you have the correct nuts.

[Tony C.]

Re: 66 A arms

Thanks for the help.
Tony

[Gary B.]

Length of nut

Tony, Micheal,

The one original A-arm nut I have measures 0.459"

Gary

[Joe L.]

Re: 66 A arms

All----

I always thought that 1966 used the locking style nut. This was a stover-style lock-nut with zinc plating. However, from your reports, it appears that earlier style, non-locking nut was used for most of 1966. Thereafter, the lock nut must have been used. As it turns out, the L66-67 lock nut had a short life in this application. It was 7/16-20 thread. For 1968-82, the bolt and nut thread changed to 7/16-14 and, consequently, a different lock-nut was used---same configuration but different thread.

[Michael H.]

Re: 66 A arms

All----

I always thought that 1966 used the locking style nut. This was a stover-style lock-nut with zinc plating. However, from your reports, it appears that earlier style, non-locking nut was used for most of 1966. Thereafter, the lock nut must have been used. As it turns out, the L66-67 lock nut had a short life in this application. It was 7/16-20 thread. For 1968-82, the bolt and nut thread changed to 7/16-14 and, consequently, a different lock-nut was used---same configuration but different thread.

I think almost everyone assumed that all 66's used the new style zincad nut Joe. Here's why. The 66 AIM sheet only lists the new 9422300 nut and there's no mention of the previous 3722855 tall nut that was shown in the 63-65 AIM.
The reason why it's not shown as being replaced during 66 production is because the AIM page that we have is not the original page. It's a replacement page.
The original page had 8 revisions and there was no space in the revision box for more so the original page was tossed/replaced with a new page. Note that the revisions begin with revision #9.

I just noticed that there was a new part number for the bolt for 66 too. Wonder what the difference was? Shorter??

[Gary B.]

'66 Upper A-arm-to-frame bolts; where to buy?

Guys,

The original upper A-arm-to-frame bolts on my '66 were 7/16-20, probably black phosphate, at least there is no hint whatsoever of zinc plating. The bolt length (not counting the head) is 2.1", with a threaded length of 1.25", and of course, it has the splines for a length of about 0.15" under the head. Would LIC sell this bolt in black phosphate for '64, '65 application?

Gary

[Michael H.]

Re: '66 Upper A-arm-to-frame bolts; where to buy?

Guys,

The original upper A-arm-to-frame bolts on my '66 were 7/16-20, probably black phosphate, at least there is no hint whatsoever of zinc plating. The bolt length (not counting the head) is 2.1", with a threaded length of 1.25", and of course, it has the splines for a length of about 0.15" under the head. Would LIC sell this bolt in black phosphate for '64, '65 application?

Gary

Gary,

I just dug out some info on the control arm bolt. The original 63-66 bolt, # 3719948, is shown as a 7/16"-20 X 2 1/8".

The replacement, # 3888247, probably used late 66 through 67, is shown as a 7/16"-20 X 2 1/4".

At some point, the 948 was discontinued and replaced by the longer 247 in service for past models.

My May printing of the 66 parts book only shows the 948. I assume the slightly longer 247 entered production in late 66 MY.


I agree, the plating would be black.