66 Small Block Motor Mounts

[J M.]

What is the correct GM number for the 66 small block motor mount? According to the AIM, it should be either a 3886456 or a 3886466. I can't make out the numbers. Neither of those numbers show up on GMPartsDirect as a valid number. Thanks.

[Michael H.]

Re: 66 Small Block Motor Mounts

Dan,

Pretty sure it was the 466. I'll look and make sure. This part was discontinued decades ago and replaced many times with newer design interlocking mount assy's.

I believe the correct configuration is currently being reproduced but I'm not sure who makes it.

[J M.]

Re: 66 Small Block Motor Mounts

Well, I went to my local speed shop and was going to buy some from him. They were made in India for Anchor and I refuse to put that crap on my car. If you think the Chinese stuff is bad, take a look at the Indian mounts. Horrible.

[Michael H.]

Re: 66 Small Block Motor Mounts

Yes, I've seen many of the parts that come from "over there". I'd rather have the old worn out original parts on my car.

[Joe L.]

Re: 66 Small Block Motor Mounts

Dan-----

The GM #3886466 were the ones originally used for 1966 Corvettes. They were also used for 1967 and 1968 Corvettes. You won't find them in the GM parts system today, though. They were discontinued in March, 1971 and replaced by the locking style mounts, a version of which is still available today.

As others have mentioned, virtually all, if not all, of the non-locking mounts available today are of foreign manufacture. If there's a US source for these things, I don't know what it is. These mounts (and, also, many of the locking style mounts, too) are manufactured in India, China, Korea, and other countries. I've found the Korean-manufactured examples to be about the best, at least as far as appearance goes. However, most of the mounts are configured a bit differently from the originals and the steel components of the assembly are thinner.

Actually, I don't recommend the use of the non-locking style mounts, at all. A brokem motor mount can cause a lot of other "problems" that you don't want to have. If you think that non-original-configuration motor mounts are bad, you should see some of the "non-original configuration" that can be created by a broken motor mount. Given the fact that long in-use original mounts are highly suspect and should be replaced and current "reproductions" of the non-locking mounts are of questionable quality, I recommend only the current GM locking mounts. They're expensive, though. FAR more expensive than aftermarket of either the locking or non-locking style.

[J M.]

Re: 66 Small Block Motor Mounts

Joe:
Do you happen to have a part number for the currently available mount?

[Eugene B.]

Re: 66 Small Block Motor Mounts

Dan,
The non-interlocking motor mounts that I purchased for my '65 came from LIC. They look excellent and original in every way.

I chose the non-interlocking design because I read in a couple of places that if the newer (interlocking design is used) the ignition shielding will have to be modified.

Hope this information is useful. Good luck on your '66.

Regards,
Gene

[Gary C.]

Motor Mounts-Caution on After Market

FYI - most of the after market motor mounts are either from China or India and that includes NAPA and in my experience DO NOT FIT! Long Island Corvette worked well as per the previous post. JMTCW Gary....

[Joe L.]

Re: 66 Small Block Motor Mounts

Dan------

GM #6258154. They currently GM list for $77.86/each.

[Joe L.]

Re: 66 Small Block Motor Mounts

Gene-----

Yes, the locking style mounts do require modification of the lower ignition shields. An alternative is to purchase the 70+ lower shields which are designed to fit with the locking style mounts. These will fit perfectly for earlier small block applications.

[J M.]

Re: 66 Small Block Motor Mounts

Thanks Joe. Is it possible to tell me what applications this mount, #3990914, will fit?

[Joe L.]

Re: 66 Small Block Motor Mounts

Dan------

It's a 1971 locking style replacement for the non-locking mount originally used for the following applications:

64-67 Chevy II with V-8

68-69 Camaro with V-8

68 Chevelle with 307

63-68 passenger car with small block V-8

58-62 passenger with small block V-8

60-62 series 10-20 light truck with Powerglide

It was also used in PRODUCTION and SERVICE for the following:

1970-71 Camaro with 6 cylinder, 307

1970-72 Chevelle with 307

1970-71 Chevy II with 307

70-72 passenger car with 2 barrel carb and 350

For some of the above-referenced applications the 3990914 mount was used for the right side only with a different mount used for the left side.

[J M.]

Re: 66 Small Block Motor Mounts

What's puzzling to me is that the Anchor mount that is cross referenced to this 3990914 mount is what fits my car. The Anchor mount that is supposed to fit my 66 is too big.

[Joe L.]

Re: 66 Small Block Motor Mounts

Dan-----

I don't know what the story is here. I can tell you that the 3990914 mount was never used for a Corvette application. The locking style mount for Corvette was 3990916.

[J M.]

Re: 66 Small Block Motor Mounts

Thanks Joe for all of the info. Today I received from my local GM dealer a 6258154 mount as you recommended. It is the correct mount and fits perfectly. It is made in Canada and is far superior to any of the other mounts I have seen. Well worth it to me.