1963-1969 & 1970-1974 LH "V" Ignition Wire Shield comparison

[David L.]

In the 1st and 2nd photos is a 1963-1969 LH "V" ignition wire shield (GM # 3819761 in the Chevrolet Radio Parts Catalog) above what I believe to be a 1970-1974 LH "V" ignition wire shield (GM # 3987341 as shown in a 1975 Corvette Parts Catalog dated Sept. 1974). The two shields are almost identical except for the difference in the way the shields are trimmed on the bottom left side as shown in the 2nd photo.

I am a bit confused as I found a photo of a NOS 3987341 "V" shield on the web (3rd photo) and the support on the left side is at an angle similar to the 1975 and later "V" shield, GM # 361079.

THE QUESTION: Is my what I believe to be a 3987341 "V" shield an early 1970 version or is it really a late version of a 1963-1969 "V" shield, GM # 3819761?

The 1963-1969 Corvette assembly manuals list the LH "V" Shield as 3819763, the left support as 3819760, the right support as 3819765 plus the 4 rivets. The assembly of these parts would be GM # 3819761 as shown in the parts catalogs. The left support is stamped "B" and the right support is stamped "AS" as shown in the photo.

The 1970 Corvette assembly manual lists the LH "V" Shield as 3973403, the left support as 3973402, the right support as 3819765 plus the 4 rivets. The assembly of these parts would be GM # 3987341 as shown in the parts catalogs. The right support is stamped "AS" as shown in the photo.

The 1978 Corvette assembly manual lists the LH "V" Shield as 354423, the left support as 3973402, the right support as 3819765 plus the 4 rivets. The assembly of these parts would be GM # 361079 as shown in the parts catalogs. I have one of these in my collection and the shield part is stamped "354423" and "AT", the left support is stamped "3973402" along with a large letter "C", and the right support is stamped "B".

Dave

[Joe L.]

Re: 1963-1969 & 1970-1974 LH "V" Ignition Wire Shield comparison

In the 1st and 2nd photos is a 1963-1969 LH "V" ignition wire shield (GM # 3819761 in the Chevrolet Radio Parts Catalog) above what I believe to be a 1970-1974 LH "V" ignition wire shield (GM # 3987341 as shown in a 1975 Corvette Parts Catalog dated Sept. 1974). The two shields are almost identical except for the difference in the way the shields are trimmed on the bottom left side as shown in the 2nd photo.

I am a bit confused as I found a photo of a NOS 3987341 "V" shield on the web (3rd photo) and the support on the left side is at an angle similar to the 1975 and later "V" shield, GM # 361079.

Is "my" 3987341 "V" shield an early 1970 version or is it really a late version of a 1969 shield, GM # 3819761?

Dave

Dave------



There were only 2 SERVICE part numbers for the left side shields during the 1963-74 period. The first was GM #3819761. This was used from 1963 through at least September, 1969, if not the entire 1969 year. The 3819761 are the shields shown in your first photo. Apparently, a slight change was made for this shield at some point without a change in part number. This resulted in the change in "cutouts" seen in the two shields you depict. Nevertheless, both of these shields are GM #3819761.


The second SERVICE shield was GM #3987341. This is the shield shown in your second photo. This shield differed from the 3819761 in the configuration of the left end. It was more "cutaway" than the 3819761. This was to provide clearance for the locking style motor mounts used for the 1970+ model years. It's possible that these were also used for very late 1969 although I doubt it. If the locking style mounts were used for the very late 1969 model year, then the 3987341 would also be so-applicable.

The non-locking style motor mounts were discontinued from SERVICE by GM in March, 1971 and replaced by the locking style for all 1963-69 Corvette applications. The locking style mounts included directions for modifying the Corvette shields to, effectively, convert a 3819761 to a 3987341. Non-locking style mounts continued to be available in the aftermarket for those foolish enough to want to continue to use them.

You will notice that I mentioned above that the 3819761 and 3987341 were SERVICE part numbers. These part numbers were never used in PRODUCTION. That's because, in PRODUCTION, the shields were supplied without attached reinforcements/supports. The reinforcements/supports were riveted to the shields at St. Louis. Of course, that seems dumb but that's, apparently, how it was. The PRODUCTION part numbers for the left side shields exclusive of the reinforcements/supports were 3819763 (63-69) and 3973403 (70-74). In any event, once the shields were fitted with the reinforcements/supports at St. Louis, they "became" the 3819761 and 3987341 as installed on the cars.

Everything I've said above is also applicable to the right side shields although the part numbers were obviously different.

[David L.]

Re: 1963-1969 & 1970-1974 LH "V" Ignition Wire Shield comparison

Joe,

Thanks for your explanation. It's the only thing that make sense. As shown in the photo below both LH "V" shields are 3819763 (shield only, part number in assembly manuals) and GM # 3819761 (shield asm., service part number). As I understand the top LH "V" shield would be correct for 1963-1968 Corvettes and the bottom LH "V" shield would be 1969 Corvette only because go the "locking type" motor mounts.

Dave

[Joe L.]

Re: 1963-1969 & 1970-1974 LH "V" Ignition Wire Shield comparison

Joe,

Thanks for your explanation. It's the only thing that make sense. As shown in the photo below both LH "V" shields are 3819763 (shield only, part number in assembly manuals) and GM # 3819761 (shield asm., service part number). As I understand the top LH "V" shield would be correct for 1963-1968 Corvettes and the bottom LH "V" shield would be 1969 Corvette only because go the "locking type" motor mounts.

Dave

Dave-------


I don't know when the change was made to the "cutaway" on the bottom of the shields. However, this cutaway would have nothing to do with accommodation for the locking style mounts. Both of the shields pictured in this photo would be GM #3819761 and both could only be used with the original-style, non-locking motor mounts.

The GM #3987341 had the upper left end of the shield modified to accommodate the locking style mounts. Also, note the difference in the orientation of the reinforcement/support.

[David L.]

Re: 1963-1969 & 1970-1974 LH "V" Ignition Wire Shield comparison

Dave-------


I don't know when the change was made to the "cutaway" on the bottom of the shields. However, this cutaway would have nothing to do with accommodation for the locking style mounts. Both of the shields pictured in this photo would be GM #3819761 and both could only be used with the original-style, non-locking motor mounts.

The GM #3987341 had the upper left end of the shield modified to accommodate the locking style mounts. Also, note the difference in the orientation of the reinforcement/support.

Joe,

When replacing motor mounts on 63-69 Corvettes there were instructions when using "locking" motor mounts 3990916 and later 6258154. The instruction sheet was GM # 3990917. The 63-69 Corvette "V" shield assemblies, GM # 3819761 & 3819762, had to be modified as shown in the instructions for clearance purposes for these locking motor mounts.

I guess that I do not understand why the 63-69 Corvette "V" shield asm., GM # 3819761, had 2 different versions. The additional "cutaway" on the bottom of the 2nd version "V" shield must have been for made for some kind of clearance problem......but why?
This same additional "cutaway" is on the 75-82 Corvette 361079 "V" shield and I assume on the 70-74 Corvette 3987341 "V" shield as well.

Dave