1963 tach cables - 1st design & 2nd design

[David L.]

My 1963 Chevrolet Parts Catalog (Oct. 1962) lists the following tach cable for the 1963:
GM # 6409117
GM # 6409117 was replaced with GM # 6409536 in May 1963 as per Chev. Parts History.

My 1964 Chevrolet Parts Catalog (Oct. 1963) lists the following tach cables for the 1963 and 1964:
GM # 6409536 (AC CC-151), 63 Corvette
GM # 3844016, 64 Corvette
GM # 6409130, 63 Corvette (1st design) (25 1/8", wo/casing)
GM # 6409507 63-64 Corvette (2nd design) (22 1/8", wo/casing)

The 1963 AIM lists cable # 3844016 replaced with cable # 6409854 on 6-3-63 on UPC 12, sheet B1.00.
The 1964 AIM lists tach cable # 3844016 on UPC 12, sheet C3.00. This does not make any sense to me.

I have an original tach cable that measures approximately 25 1/16" (or maybe 25 1/8") with a casing that measures 24" long which I believe is from a 1st design 1963 Corvette. Both of the nuts have a casting of "AC SPEEDOMETER".

The 3" difference between the 1st and 2nd design cables is significant. Is there a 1963 expert that can explain why there were two different lengths of the 1963 tach cable?

Dave

[Loren L.]

Re: 1963 tach cables - 1st design & 2nd design

It doesn't take an "expert" to suspect a FLAWED Pts Bk description; start with the two "w/o casing"
listings - it seems clear that they are talking only about the metal guts, not the grey housing cable w/metal.
That could also be the change in May 63 referred to, a "paperwork" basis for the changeover to the black housing that doesn't actually occur until later.

[Harry S.]

Re: 1963 tach cables - 1st design & 2nd design

The outer case of my July car is one inch shorter than the outer case of my April car. Why, I have no idea but it is shorter.

[David L.]

Re: 1963 tach cables - 1st design & 2nd design

It doesn't take an "expert" to suspect a FLAWED Pts Bk description; start with the two "w/o casing"
listings - it seems clear that they are talking only about the metal guts, not the grey housing cable w/metal.
That could also be the change in May 63 referred to, a "paperwork" basis for the changeover to the black housing that doesn't actually occur until later.

Loren,

Exactly how, in your opinion, is the parts catalog "FLAWED"? I suspect that the 22 1/8" dimension is wrong. By "metal guts" I assume you mean the actual cable itself excluding the casing.

The 63 AIM lists the original tach cable assembly as GM # 3844016 and then replaced (as per the drawing) on June 3, 1963, with GM # 6409854. The 1964 AIM lists the tach cable assembly as 3844016 which is the one that was just replaced in the 1963 AIM.

Dave

[Alan D.]

Re: 1963 tach cables - 1st design & 2nd design

David, The 22 1/8" bare cable (wo/casing) is listed as the 63-64 2nd design, 6409507, in the July 63 P&A Catalog. That is the original cable on my Mar64 FI car and it has black casing.

[David L.]

Re: 1963 tach cables - 1st design & 2nd design

The out case of my July car is one inch shorter than the out case of my April car. Why, I have no idea but it is shorter.

Harry,

According to my 1982 Corvette parts catalog (Nov. 1981) in Gr. 4.342 (Speedometer cables) "Shaft length is generally 1 1/8 longer than casing dimension listed". In my opinion this statement also seems to include tach cable assemblies based on the dimensions of tach cable assemblies in Gr. 9.750 as well as physical evidence.

I assume that the tach cable assemblies in your April and July cars are original. I also assume that the cable length in your April car may be 25 1/8" with a 24" casing length. If the casing (outer case) length of the cable assembly in your July car is one inch shorter that would make the casing length 23" and the cable length 24 1/8".

My 1965, 1966, and 1967 Chevrolet Parts Catalogs (May 1965, Oct. 1965, April 1967, and July 1967) list GM # 3866126 as the part # for the 1965-1967 Corvettes with a description of "SHAFT ASSY., tach. (shaft 23" - 24 1/8" O.L.)". The May & July 1967 parts catalogs list GM # 3866126 for 1963-1967 Corvettes. GM # 3844016 was replaced with GM # 3866126 in March 1966 as per Chevrolet Parts History.

Getting back to my original question. Was the tach cable assembly routed in a different manner in "early" 1963 Corvettes?


Dave

[David L.]

Re: 1963 tach cables - 1st design & 2nd design

David, The 22 1/8" bare cable (wo/casing) is listed as the 63-64 2nd design, 6409507, in the July 63 P&A Catalog. That is the original cable on my Mar64 FI car and it has black casing.

Alan,

So the parts catalog is correct. Have you ever seen a 1st design tach cable assembly on a 1963 and how it is routed? The 1963 AIM states "route shaft under w/s wiper rods". I assume this statement is for the 2nd design.

Thanks for your comment.

Dave

[Timothy B.]

Re: 1963 tach cables - 1st design & 2nd design

I hope it's OK to resurrect an old post, I bought a grey (1963) tach cable at Carlisle and the outer housing is 21 1/4" long, would it be safe to say it's the second design. The female nuts say AC spark plug div. there is no inner cable so I need to make one.

I have a black cable in my stash that the outer housing measures exactly 2" longer at 23 1/4". The cable nuts read something different than the AC spark plug div. but I think it's typical of the black cable.