1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictures)

[Scott S.]

Car is a 1967, with L79 engine.

The first picture is a comparison between the motor mount that came off the '67, the replacement motor mount currently offered by LIC which looks very similar, and a mystery motor mount. The other three pictures are different angles of the motor mounts that came off the '67 when we disassembled it.

Were the motor mounts that came off the car correct?

What are the unknown motor mounts at the bottom of the comparison photo (picture #1)?

Thank you very much,
Scott

[Joe L.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Car is a 1967, with L79 engine.

The first picture is a comparison between the motor mount that came off the '67, the replacement motor mount currently offered by LIC which looks very similar, and a mystery motor mount. The other three pictures are different angles of the motor mounts that came off the '67 when we disassembled it.

Were the motor mounts that came off the car correct?

What are the unknown motor mounts at the bottom of the comparison photo (picture #1)?

Thank you very much,
Scott

Scott------


Per my recollection of it, the mounts that came off your car appear to be correct original mounts of GM #3886466. I have several NOS examples of this mount[none for sale] but I just don't have the energy to go dig them out. One thing I do remember about them, though, is that the 3886466 part number is embossed on the side of the rubber portion of the mount. However, I don't know that all original mounts had this embossment.

As far as the unknown mounts, I don't know what they are, but they're not Corvette mounts.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Scott------


Per my recollection of it, the mounts that came off your car appear to be correct original mounts of GM #3886466. I have several NOS examples of this mount[none for sale] but I just don't have the energy to go dig them out. One thing I do remember about them, though, is that the 3886466 part number is embossed on the side of the rubber portion of the mount. However, I don't know that all original mounts had this embossment.

Right on the money as usual Joe, thanks! I didn't see it before, but I looked again and I could make out numbers in two different places. Along the side, molded into the rubber, I found "AU" and "73", separated by about 1/2".

When I looked closely under a bright light, I can just make out the number "3886466" across the "top" rubber (my orientation is probably incorrect, I underlined it in red on the picture).

As far as the unknown mounts, I don't know what they are, but they're not Corvette mounts.

Thank you Joe!

[Bob J.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

What are the unknown motor mounts at the bottom of the comparison photo (picture #1)?

Thank you very much,
Scott

283 mounts 1958-67

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

283 mounts 1958-67

Hi Bob,

Are you saying the mystery mounts from the comparison photo in the original post are correct for all of the following?

1958 (283 cubic inch)
1959 (283 cubic inch)
1960 (283 cubic inch)
1961 (283 cubic inch)
1962 (327 cubic inch)

Also correct for:
1963-1967 (327 cubic inch)?

Here are a few more pictures:

[Bob J.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Hi Bob,

Are you saying the mystery mounts from the comparison photo in the original post are correct for all of the following?

1958 (283 cubic inch)
1959 (283 cubic inch)
1960 (283 cubic inch)
1961 (283 cubic inch)
1962 (327 cubic inch)

Also correct for:
1963-1967 (327 cubic inch)?

Here are a few more pictures:

Scott, yes they fit 283 307 and 327 in passenger cars, not Corvette.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Scott, yes they fit 283 307 and 327 in passenger cars, not Corvette.

Thank you for the clarification. These (the darker example on the left) were represented as new, USA-made correct Corvette motor mounts for a 1967 small-block and would pass Top-Flight judging, but they didn't look like the ones that came off my car.

[Joe L.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Thank you for the clarification. These (the darker example on the left) were represented as new, USA-made correct Corvette motor mounts for a 1967 small-block and would pass Top-Flight judging, but they didn't look like the ones that came off my car.

Scott-----


I don't think you'll find any better reproduction mount than the one pictured. Even finding a USA-manufactured mount is a triumph in itself.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Scott-----


I don't think you'll find any better reproduction mount than the one pictured. Even finding a USA-manufactured mount is a triumph in itself.

Hi Joe,

I think I have confused things by not attaching pictures to the previous post, and the example in my original post was of a motor mount from LIC that was dark in color (top, right).

In this post, I have attached a picture of the mount that was represented to me as being correct for a 1967 Corvette, USA-made, and would pass a manual NCRS judging inspection. This is the mount that you earlier said was not a Corvette motor mount, and Bob explained it was for 283ci and 327ci passenger cars (not Corvettes) from 1958-1967.

Just so we're all on the same page, the motor mount attached to this post (immediately below) is definitely NOT a correct motor mount for any Corvette, certainly not a 1967 Corvette small block?

[Joe L.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Hi Joe,

I think I have confused things by not attaching pictures to the previous post, and the example in my original post was of a motor mount from LIC that was dark in color (top, right).

In this post, I have attached a picture of the mount that was represented to me as being correct for a 1967 Corvette, USA-made, and would pass a manual NCRS judging inspection. This is the mount that you earlier said was not a Corvette motor mount, and Bob explained it was for 283ci and 327ci passenger cars (not Corvettes) from 1958-1967.

Just so we're all on the same page, the motor mount attached to this post (immediately below) is definitely NOT a correct motor mount for any Corvette, certainly not a 1967 Corvette small block?

Scott-----


Yes, the mount pictured in this post is NOT a Corvette mount. I thought you were referring to the LIC mount pictured in your first post. That one actually looks like one of the "foreign" mounts I've seen. Still, whether or not it's of foreign manufacture, I don't think you'll find any better or more correct mount in today's parts marketplace.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Scott-----


Yes, the mount pictured in this post is NOT a Corvette mount. I thought you were referring to the LIC mount pictured in your first post. That one actually looks like one of the "foreign" mounts I've seen. Still, whether or not it's of foreign manufacture, I don't think you'll find any better or more correct mount in today's parts marketplace.

Thanks again, Joe.

After researching motor mounts here in the archives, it seems that around 1970 the interlocking style was developed, and they were service replacements for earlier models (p/n 3990916). They came with instructions to modify the spark plug shields on C2s, or you could buy C3 spark plug shields and retro-fit them to a C2. At some point the part number changed to 6258154, and was then discontinued by GM without supercession in March 2007, according to my local Chevrolet dealer (I was hoping he could track down a set through their national network).

If I can find a set of NOS p/n 6258154, it won't be correct for judging, but that seems like the best option from a quality and safety standpoint for a car that will be driven. A set of NOS 3990916 would work too, but I don't know how well the rubber holds up sitting on the shelf all those years.

If I go with the original style (non-interlocking, non-safety type) by foreign manufacture, I'm concerned that it won't last, the mount will break, and without the interlocking safety feature, the throttle could hang wide open or the underside of the hood could be damaged (or both, or worse).

I can usually find old NOS parts with some searching, but even though these were still being produced as recently as just three years ago, I haven't been able to find a set of GM 6258154 anywhere. I have read that there are compatible U.S. motor mounts made by Anchor, but at some point they began making these mounts overseas, and I don't know how distinguish the U.S. made from the foreign-made Anchor brand.

I'll keep looking. Is the condition of the rubber on old (but never used) motor mounts something I need to be concerned about, or should a NOS set of p/n 3990916 from the 1970s (or 6258154 from the 1980s-90s?) be fine as long as they've been stored properly?

[Joe L.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Thanks again, Joe.

After researching motor mounts here in the archives, it seems that around 1970 the interlocking style was developed, and they were service replacements for earlier models (p/n 3990916). They came with instructions to modify the spark plug shields on C2s, or you could buy C3 spark plug shields and retro-fit them to a C2. At some point the part number changed to 6258154, and was then discontinued by GM without supercession in March 2007, according to my local Chevrolet dealer (I was hoping he could track down a set through their national network).

If I can find a set of NOS p/n 6258154, it won't be correct for judging, but that seems like the best option from a quality and safety standpoint for a car that will be driven. A set of NOS 3990916 would work too, but I don't know how well the rubber holds up sitting on the shelf all those years.

If I go with the original style (non-interlocking, non-safety type) by foreign manufacture, I'm concerned that it won't last, the mount will break, and without the interlocking safety feature, the throttle could hang wide open or the underside of the hood could be damaged (or both, or worse).

I can usually find old NOS parts with some searching, but even though these were still being produced as recently as just three years ago, I haven't been able to find a set of GM 6258154 anywhere. I have read that there are compatible U.S. motor mounts made by Anchor, but at some point they began making these mounts overseas, and I don't know how distinguish the U.S. made from the foreign-made Anchor brand.

I'll keep looking. Is the condition of the rubber on old (but never used) motor mounts something I need to be concerned about, or should a NOS set of p/n 3990916 from the 1970s (or 6258154 from the 1980s-90s?) be fine as long as they've been stored properly?

Scott-----

I believe the real problem with old motor mounts involves those exposed to heat, weather, UV radiation, and automotive chemicals. These are the factors that degrade rubber. Of course, to some degree, just age is a factor, too. However, I have a large number of NOS Corvette motor mounts [none for sale] including 3886466 (non-locking type), 3980701, 3990916 and 6258154 and I would not be at all concerned about using any of them.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

Thanks Joe, that's good news, I'll keep an eye out.

[Scott S.]

Re: 1967 motor mounts (L79 engine) - These were on the car, are they correct? (pictur

I found a set of motor mounts that are described as older NOS Anchor brand, from when Anchor motor mounts were still made in the USA (if I understand that correctly). I created a composite of the older NOS Anchor mounts, the LIC motor mount (said to be USA-made, but manufacturer not given), and the original motor mounts that were on the '67.

Comments or observations, information about Anchor motor mounts, etc. are welcome (encouraged, even!).