"69 350 engine spark plug heat shields

[Kevin S.]

Wanting to confirm what the correct finish is for the four inner spark plug boot heat shields. I believe the inner shields are stamped aluminum and dull flash-chrome finish just like the outer plug boot heat shields but I want to check first before proceeding?

PN 3817657 for #2 & #4 cylinders and same PN for #5 & #7 cylinders
PN 3919807 for #1 & #3 cylinder
PN 3815084 for #6 & #8 cylinders

Thank you in advance for your input. First time using the new and improved web site upgrade. Had some challenges uploading the photos. Only able to upload one. I'll see if I can come back in and edit and add more pics.

Kevin
IMG_E2109.jpg

[Joe L.]

Wanting to confirm what the correct finish is for the four inner spark plug boot heat shields. I believe the inner shields are stamped aluminum and dull flash-chrome finish just like the outer plug boot heat shields but I want to check first before proceeding?

PN 3817657 for #2 & #4 cylinders and same PN for #5 & #7 cylinders
PN 3919807 for #1 & #3 cylinder
PN 3815084 for #6 & #8 cylinders

Thank you in advance for your input. First time using the new and improved web site upgrade. Had some challenges uploading the photos. Only able to upload one. I'll see if I can come back in and edit and add more pics.

Kevin

First, a little definition of terms: the SPARK PLUG SHIELDS are the INNER shields which attach to the block with a single 1/4" bolt. The RADIO FREQUENCY INTERFERENCE (RFI)SHIELDS are the OUTER shields which attach to brackets retained by exhaust manifold bolts.

The spark plug shields are zinc plated steel. The RFI shields are chrome plated steel or stainless steel, depending on the particular shield. As I recall, the left rear shield is stainless steel.

Regardless of what anyone says, I do not think that the 3919807 spark plug shield was originally used for any 1969 small block. I know, for sure, it was not used for my original owner, 1969 small block. If the 3919807 shield is used for the left front position, then an RFI shield cannot also be installed for the left front position..

I believe the spark plug shield used for the left front and right rear position was GM #3917664 and the right front and left rear position was the GM #3917663.

[Kevin S.]

Good Morning, Joe,
Thank you for the clarification of terms. Yes, I was talking about the spark plug shields. Zinc-plated steel finish, got it - thanks.

Below are photos of the bottom of the spark plug shields that I took off the car. I masked the yellow stamp number to preserve it. I do not know if this is OEM. These yellow stamp numbers were on the car when we bought it in 2009. There are yellow stamp numbers on the underside of the #1-#3, #5-#7, #2-#4 spark plug shields. There is no yellow stamp on the underside of the #6-#8 spark plug shield.

These numbers matched my AIM book:
Spark plug wiring, shields, coil
UPC 6 B6
Page J 204 in the AIM book that I have for 1969

IMG_2115.jpg IMG_E2117.jpg IMG_E2118.jpg

[Joe L.]

Good Morning, Joe,
Thank you for the clarification of terms. Yes, I was talking about the spark plug shields. Zinc-plated steel finish, got it - thanks.

Below are photos of the bottom of the spark plug shields that I took off the car. I masked the yellow stamp number to preserve it. I do not know if this is OEM. These yellow stamp numbers were on the car when we bought it in 2009. There are yellow stamp numbers on the underside of the #1-#3, #5-#7, #2-#4 spark plug shields. There is no yellow stamp on the underside of the #6-#8 spark plug shield.

These numbers matched my AIM book:
Spark plug wiring, shields, coil
UPC 6 B6
Page J 204 in the AIM book that I have for 1969

IMG_2115.jpg IMG_E2117.jpg IMG_E2118.jpg

Kevin------


The GM #3817657 was replaced for SERVICE by the GM #3917663 in January, 1968. The GM #3815084 was replaced for SERVICE by the GM #3917664 in May, 1968. Regardless of what the AIM states, I would expect that the later shields were used on all 69's. However, it matters little because I believe there is virtually no difference between the early and late part numbered shields.

Usually, the yellow printed part numbers indicate a SERVICE part but I suppose it's possible they were used in PRODUCTION.

Regarding your GM #3919807 left front shield, was a chromed or stainless RFI shield installed over it?

[Kevin S.]

Kevin------


The GM #3817657 was replaced for SERVICE by the GM #3917663 in January, 1968. The GM #3815084 was replaced for SERVICE by the GM #3917664 in May, 1968. Regardless of what the AIM states, I would expect that the later shields were used on all 69's. However, it matters little because I believe there is virtually no difference between the early and late part numbered shields.

Usually, the yellow printed part numbers indicate a SERVICE part but I suppose it's possible they were used in PRODUCTION.

Regarding your GM #3919807 left front shield, was a chromed or stainless RFI shield installed over it?

Hello Joe,
Thank you for the additional details. All of the chromed or stainless RFI shields were removed on this car. I have ordered Corvette Central PN 473052 69-70 Lower Ignition Shield Set to put them back on the car as part of my NCRS restoration journey.

https://www.corvettecentral.com/c3-68-82/ignition-distributor/350-ignition-shielding/69-70-lower-ignition-shield-set-early-70-473052

Kevin

[Terry M.]

[QUOTE=Joe Lucia (12484);n1572260]

Regardless of what anyone says, I do not think that the 3919807 spark plug shield was originally used for any 1969 small block. I know, for sure, it was not used for my original owner, 1969 small block. If the 3919807 shield is used for the left front position, then an RFI shield cannot also be installed for the left front position..
/QUOTE]

Joe
I'll be the one who says both the 3919807 spark plug shield on the left front and the RFI shield CAN be installed on the left front because my original-owner 1970 LT1 was so equipped when it came to me. Those two items were forced into position and both the spark plug shield and RFI shield were bent from what I believe was their original configuration, but Someone before the car came to me was able to do it.

If I remember correctly your 1969 Corvette was assembled in October 1969 - My Corvette was assembled in late January 1970. Our builds were not that far apart if my memory is correct.

I believe what we have here is an example of how each Corvette is a unique vehicle and one should not use any one car as an example of how they were all built. If one could find enough unmolested Corvettes to have a definitive survey of these kinds of details (and one would need many hundreds, if not thousands of examples for a definitive survey) then we could say what is typical factory production. Failing that kind of definitive detail I think we have to say "do what you like."

[Joe L.]

Hello Joe,
Thank you for the additional details. All of the chromed or stainless RFI shields were removed on this car. I have ordered Corvette Central PN 473052 69-70 Lower Ignition Shield Set to put them back on the car as part of my NCRS restoration journey.

https://www.corvettecentral.com/c3-68-82/ignition-distributor/350-ignition-shielding/69-70-lower-ignition-shield-set-early-70-473052

Kevin

Kevin------

When you get the RFI shields you'll find that the left front shield will not fit over the 3919807 spark plug shield.

[Kevin S.]

Kevin------

When you get the RFI shields you'll find that the left front shield will not fit over the 3919807 spark plug shield.

Hello Joe & Terry,
I saw each of your notes regarding the spark plug shield and the RFI shield fit on the LH front position. I'll attempt to make it work. I have the engine out of the car at the moment so there is plenty of room to maneuver and possibly modify. I did see some historical posts that mentioned putting everything on loose and then tightening once the form and fit was right. I'll give that a try prior to bending and modifying either the plug heat shield and / or the RFI shield.

Thank you both for your comments.

Kevin

[Kevin S.]

[QUOTE=Terry McManmon (3966);n1572347]

Regardless of what anyone says, I do not think that the 3919807 spark plug shield was originally used for any 1969 small block. I know, for sure, it was not used for my original owner, 1969 small block. If the 3919807 shield is used for the left front position, then an RFI shield cannot also be installed for the left front position..
/QUOTE]

Joe
I'll be the one who says both the 3919807 spark plug shield on the left front and the RFI shield CAN be installed on the left front because my original-owner 1970 LT1 was so equipped when it came to me. Those two items were forced into position and both the spark plug shield and RFI shield were bent from what I believe was their original configuration, but Someone before the car came to me was able to do it.

If I remember correctly your 1969 Corvette was assembled in October 1969 - My Corvette was assembled in late January 1970. Our builds were not that far apart if my memory is correct.

I believe what we have here is an example of how each Corvette is a unique vehicle and one should not use any one car as an example of how they were all built. If one could find enough unmolested Corvettes to have a definitive survey of these kinds of details (and one would need many hundreds, if not thousands of examples for a definitive survey) then we could say what is typical factory production. Failing that kind of definitive detail I think we have to say "do what you like."

Hello Terry,
You were close. My build date was Thursday, October 31, 1968...number 405. It's a Halloween car. Nothing special about that day other than it's interesting to me.

Kevin

[Joe L.]

[QUOTE=Terry McManmon (3966);n1572347]

Regardless of what anyone says, I do not think that the 3919807 spark plug shield was originally used for any 1969 small block. I know, for sure, it was not used for my original owner, 1969 small block. If the 3919807 shield is used for the left front position, then an RFI shield cannot also be installed for the left front position..
/QUOTE]

Joe
I'll be the one who says both the 3919807 spark plug shield on the left front and the RFI shield CAN be installed on the left front because my original-owner 1970 LT1 was so equipped when it came to me. Those two items were forced into position and both the spark plug shield and RFI shield were bent from what I believe was their original configuration, but Someone before the car came to me was able to do it.

If I remember correctly your 1969 Corvette was assembled in October 1969 - My Corvette was assembled in late January 1970. Our builds were not that far apart if my memory is correct.

I believe what we have here is an example of how each Corvette is a unique vehicle and one should not use any one car as an example of how they were all built. If one could find enough unmolested Corvettes to have a definitive survey of these kinds of details (and one would need many hundreds, if not thousands of examples for a definitive survey) then we could say what is typical factory production. Failing that kind of definitive detail I think we have to say "do what you like."

Terry------

My 1969 was built mid-September, 1969. It was not built with the 3919807 spark plug shield. It had the 3917664 (or 3819084).

At one point, I installed the 3919807 and tried to install the original RFI shield over it. Try as I may, there was no way I could find for it to work. However, I was not willing to bend either shield to "make it work".

I believe the 3919807 shield was designed for use on non-Corvette small block applications beginning for the 1969 model year when the temperature sender was re-located from the intake manifold to the left side cylinder head. Somehow, it got incorrectly specified for Corvette small blocks. Corvettes, of course, were the only Chevrolet small blocks with RFI shields. The forward left RFI shield was redesigned for the temp sender. However, compatibility with the 3919807 was neglected in the design.

[Terry M.]

[QUOTE=Kevin Saxton (52665);n1572389]

Hello Terry,
You were close. My build date was Thursday, October 31, 1968...number 405. It's a Halloween car. Nothing special about that day other than it's interesting to me.

Kevin

Kevin
I am sorry I wasn't clearer in my post. I thought it was Joe's car that was built in October. I didn't know when your car was built, but given your car is closer to Joe's than mine you might want to mimic his build. Again, however, I think this detail is optional for anyone is a similar situation. We simply don't have enough data to make a call. I can't picture the St Louis workers struggling to make this install.

There are some unique paint features to early LT-1s such as mine, and other earlier LT-1s I have seen, so there is no reason not to believe there were other minor details that are different as well.