I have my engine out for a refresh and want to replace the motor mounts when I put it back in. Thought this would be pretty straight forward but it turns out there are several different mounts available.

My car is a mostly stock 70LT1. I will not be putting in a higher hp engine and will never race the car. Who makes the right motor mount? I prefer a USA made stock apperaring unit.

Thanks

 

I purchased the GM replacement mounts from my local GM Restoration Parts dealer. They have a very close to stock appearance. The box on mine indicated they were made in Canada.

Tried some aftermarket mounts from some of the Corvette vendors - one sent the wrong mounts. Those mounts were from the same manufacturer as the mounts from Auto Zone - difference was Auto Zone could find the correct ones. I went with the GM replacements because I didn't like the aftermarket quality for "stock appearing" mounts.

 

2 styles of engine mounts exist for the sb chevy
They are pictured below:
Note the bottom mount is the better interlocking type.
It is designed such that if the rubber breaks apart, the mechanical locking components prevent the engine from lifting under hard accelleration and ripping the fan into the shroud or possibly through the hood.


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These stock style rubber mounts are OK for general driving, but if you are a rev head, and like to burn a bit of rubber with hard takeoffs, they will break.... and it's the left mount which splits, as shown below.



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A very cheap and effective low cost means to prevent the mount from splitting is to drill a hole (or 2) and fit a 1/4" bolt through the mount to prevent over extension of the rubber.
The bolt is secured with a nylok nut, but only tightened to the point of taking up the free play. The rubber cushion still provides damping of vibrations to the chassis. But under full throttle clutch dumps, the engine torque twist is limited by the secured bolt.




Other options: you can spend more on poly mounts, but they can also be prone to fail if you have any oil or fuel leaks in the vicinity of the mounts. Still use the interlocking type, even with poly mounts.

Or, of course, you could use solid engine mounts.
If your engine is well balanced and running smooth, it may be reasonably vibration free when driving. And you definitely won't have issues with breaking a solid engine mount.

 

Thanks for the information! When you mention the two mounts is there also one that is wider and one that is taller? When I removed mine it looks like someone had changed the left one and used the wrong mount. It is wider and would never tighten up unless you shim it which would be stupid to do.

I drive the car really quite sane 99% of the time. I actually like the C3 for the looks and the sound not the speed though going through the gears puts a big smile on the face. Sounds like the stock GM type would work fine for my application. Do any of the vendors sell this or is it strictly a GM product?

 

Perhaps a local resident may help answer that.....

The mounts I bought were from a a local auto parts vendor....
down under, in Australia

 

That may be to far to go just for new motor mounts but it sure would be a nice trip!