Stock Cat heat shield?

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CrammerGram69

Master Mechanic
Nov 15, 2019
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I am Almost ready to get a new exhaust on my car. It's missing the Cat Conv heat shield, I know it's missing because there are Tabs on the floorboard. it was gone when i got the car. Were they all the same design, or Changes after 1981-82? and would i need to find one from Malibu to fit my LeMans?. (3.8 v6). Single Pass ext.

I can only find 1 on eBay currently. Will this fit? Catalytic converter heat shield 78-88 G body
 

69hurstolds

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I know it's hard to fathom, but I actually have an NOS heat shield in my parts stash. P/N 25512619. Fits a plethora of G-body cars, but it's 82-up.

80-81 was 25505917 superseded to 25507682. Now, I can't find anything concrete to say the 619 is the same as the 917/682 shields. V6 or V8, didn't make any difference on engines.

Unfortunately, those part numbers don't correlate to each other, so I don't know what, if any differences there are.

Best to get the dimensions between the screw holes and ask the seller if that correlates to the holes in his shield.
 
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69hurstolds

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The ebay guy is another example of people assuming every 78-88 part interchanges. That may, or may not, be true. Of course, they don't bother to actually check to be sure, and that's why they suck at what they do. Not saying it won't or will fit your pattern, though, as part number changes can occur just due to supplier contracts.
 
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69hurstolds

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Found it. Here's some approximate measurements that might help you. The part the guy has LOOKS like a 619, but who knows.

25512619 shield 1.JPG

25512619 shield 2.JPG


Approx 11.25"
25512619 shield 3.JPG



Approx. 9-3/8"
25512619 shield 4.JPG



Approx. 12.5"
25512619 shield 5.JPG


Aprox. 12-5/8"
25512619 shield 6.JPG
 
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Clone TIE Pilot

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Galaxy far far away
One thing to keep in mind is that the Buick 3.8 used larger cats than the V8 options.
 
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CrammerGram69

Master Mechanic
Nov 15, 2019
430
140
43
SW, Michigan
I know it's hard to fathom, but I actually have an NOS heat shield in my parts stash. P/N 25512619. Fits a plethora of G-body cars, but it's 82-up.

80-81 was 25505917 superseded to 25507682. Now, I can't find anything concrete to say the 619 is the same as the 917/682 shields. V6 or V8, didn't make any difference on engines.

Unfortunately, those part numbers don't correlate to each other, so I don't know what, if any differences there are.

Best to get the dimensions between the screw holes and ask the seller if that correlates to the holes in his shield.
Gotcha. Well, that is still some pretty solid info to know! A friend of mine on FB messaged me he has one for $20, but i am waiting on photo's and/or what year it came from. Did the older cars get bolted-on like the one in my eBay link, or? I have been up for a few solid HRs looking though this damn 3300pg 76-81 Pontiac Parts catalog.. lol I swear sometimes the dedication i put into this! LOL
 

CrammerGram69

Master Mechanic
Nov 15, 2019
430
140
43
SW, Michigan
The ebay guy is another example of people assuming every 78-88 part interchanges. That may, or may not, be true. Of course, they don't bother to actually check to be sure, and that's why they suck at what they do. Not saying it won't or will fit your pattern, though, as part number changes can occur just due to supplier contracts.
Agreed. Many parts i have come across for my car being a LeMans is usually 1 - 3 years only. :/ Hence the 6 years of finding parts...
 

69hurstolds

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It'll be found in group 3.690. Under "Shield"

Pontiac parts book shows the same- 25507682 for 80-81 any engine in an A body. Which used to be 25505917.
 
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69hurstolds

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Yes, the "older" ones got bolted on with small screws, just like the later ones. Again, they may be bolted up to the same spots. I'm just not familiar with what an 80-81 shield looks like.

Screws are hex washer head style, M4.2x1.41x10. GM p/n 11503617, superseded to 11515959.
 
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