396 motor mounts, like AIM, but not like Judging guide

[William B.]

I have a 65 396 coupe with 32 k miles, complete original drivetrain, never been out. I am completely restoring it and have found a discrepancy with the motor mounts? Judging guide states one bolt front to rear and other bolt rear to front, I understand that but my mounts are different.
I checked the AIM and it lists 3881715 and 16, which is what I have, part #'s on mounts, with a welded nut attached to the mount, showing 1 bolt and washer per side, not washer and locking nut.
Could this be a misprint in the judging guide?, Pics attached

[Mike M.]

Re: 396 motor mounts, like AIM, but not like Judging guide

bill: never seen a weld nut on the mount but i haven't seen them all. i'd go with the JM if i were restoring a 396. is yours early mid or late production? mike

[William B.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Mike, I found the same part #'s on the mounts as listed in the AIM, I find it hard to believe the mounts were ever replaced on this car, then especially hard to believe they were replaced with the part #'s listed in the AIM. Please look at attached pic of the mount part #

[Mike M.]

Re: 396 motor mounts, like AIM, but not like Judging guide

bill: early, mid or late production? did u check with KC? mike

[William B.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Last week of july 65, very late car, is KC ever on the discussion board?

[Domenic T.]

Re: 396 motor mounts, like AIM, but not like Judging guide

As I remember the bolt went from rear to front on the passenger side because of the fuel pump. The pass bolt wouldn't come out or go in with the pump in place. That being said both mounts were the same. The welded nut would be the same on both, but when mounted side to side the pass side bolt would have to be inserted from the back on the pass side.

Dom

[Mike M.]

Re: 396 motor mounts, like AIM, but not like Judging guide

domenic: i hadn't thought of it till i read your post but since the pass side weld nut would have to be closest to fuel pump, if the mounts are identical, then the weld nut mounted on the drivers side, would have to be facing the firewall. i'd think if the mounts have the same #'s embossed in their rubber material, then the driver side nut would have to face the firewall.
Bill: KC rarely if ever checks the tab. you'll have to phone him. # is on page 2 of restorer mag. mike

[Domenic T.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Mike,
Thanks for understanding, I do have a problem explaining. And yes, when put on the pass side the nut would be on the front to save the mech from pulling the fuel pump.

Dom

[Duke W.]

Re: 396 motor mounts, like AIM, but not like Judging guide

It's interesting that the AIM sheet shows the bolt and washer, but no nut, which implies a nut integral with the motor mount.

Duke

[Joe L.]

Re: 396 motor mounts, like AIM, but not like Judging guide

I have a 65 396 coupe with 32 k miles, complete original drivetrain, never been out. I am completely restoring it and have found a discrepancy with the motor mounts? Judging guide states one bolt front to rear and other bolt rear to front, I understand that but my mounts are different.
I checked the AIM and it lists 3881715 and 16, which is what I have, part #'s on mounts, with a welded nut attached to the mount, showing 1 bolt and washer per side, not washer and locking nut.
Could this be a misprint in the judging guide?, Pics attached

William-------


These mounts almost have to be the originals. I cannot find that mounts GM #3881715 or 3881716 were ever available from GM in SERVICE.

[William B.]

Re: 396 motor mounts, like AIM, but not like Judging guide

When I first saw these mounts on my 396 car I assumed they were not original, But all indications showed me they were never removed?

I looked at the JG and no indication a mount like this was ever used?? Then in looking through the AIM, there it was, my mounts and even the part #"s in the AIM as was imprinted on my mounts.

I will put these mounts back on my car, It will go through judging at regional and national levels, Hopefully KC or some of the well experienced judges will realize I have factory installed mounts and not like anything described in the Judging Guide.

[Domenic T.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Bill,
There was a cable service bilitin to use it on ALL mounts, because the engine would lift on the driver's side when the rubber failed, which would pull the carb WIDE open, and the old folks looked like DRAG racers, till they smashed into the car in front or otherwise.

Dom

[Joe L.]

Re: 396 motor mounts, like AIM, but not like Judging guide

When I first saw these mounts on my 396 car I assumed they were not original, But all indications showed me they were never removed?

I looked at the JG and no indication a mount like this was ever used?? Then in looking through the AIM, there it was, my mounts and even the part #"s in the AIM as was imprinted on my mounts.

I will put these mounts back on my car, It will go through judging at regional and national levels, Hopefully KC or some of the well experienced judges will realize I have factory installed mounts and not like anything described in the Judging Guide.

William------


These mounts were apparently used only for 1965 L-78. Whether they were used for all of these cars there is no way of knowing at this point. However, I have absolutely zero doubt that these are original to your car. The part numbers, themselves, look like early 1966 model year part numbers but, as far as I can tell, these mounts were not used for any 1966 Corvette. So, it's possible that they were actually only used for later 1965 L-78. If you look closely in the AIM you will note that it looks like the hand-written printing for the mount part numbers looks different than that for the other part numbers on the page even though there is no change indicated in the revision block.

These are very odd mounts in that they are non-symmetrical. That's why there are different part numbers for either side. This is, of course, due to the fact that the nut is welded to one of the mount frame's ears. So, these are the only non-symmetrical motor mounts used for any 1963-82 Corvette. ALL other mounts were symmetrical and the same mount is used for either side. You will also note that it appears that one of the ears of the mount is welded to the rest of the frame rather than simply being fabricated from a single piece as are all other 63-82 Corvette motor mounts.

Why was this done? I have no idea. Apparently, it was a short lived design. For 1966 all Corvettes got new mount GM #3886466 which also became SERVICE for all 1963-65 Corvettes. The 3886466 is symmetrical and the same mount is used for both sides.

[Paul D.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Just curious and not trying to be argumentative, but looking at the AIM drawing and the photo of what appears to be the passenger (R) mount and considering that the mounts are asymmetrical, would the bolts not have to be installed from the front on both sides? Can the bolt be installed from the front on the passenger side with a big block? I assume fuel pump was installed prior to engine installation. William, were your mounts installed with bolts going front to back as pictured in the AIM or reversed?

[William B.]

Re: 396 motor mounts, like AIM, but not like Judging guide

Both bolts installed from the rear, only way it can work, Judging guide is wrong for this car.