IROCZ1989

iTrader: (1)

Well first off Im close now to dropping the 421 in. I have decided on UMI solid mount kit. Problem is UMI says there kit fits g body and f body. F body clamshells are side specific. Clearly.



Picture courtesy of JohninRI.
The moroso solid mounts that bolt to the k member are side specific. They take up the difference there. But their clamshell mounts are not. The difference is in the k member pads. Factory thirdgen k member pads are not side specific, the clamshells are. If you put them on the wrong side the motor will not sit correctly and will be close to one side. Now on to the UMI kit. They tell me nothing is side specific and their mounts fit gbody as well as fbody. Factory g body clamshells 334970 are used for both sides. Mine are 333971 on one side and different on the other 14039436 . Obviously they are differnet in size too and apearance. Look at the picture. Plus I dont know of anyone running there solid mounts on a fbody. That said here is what Im trying to achieve. Solid mounts because My exhaust is close to underbody and poly raise it up against the frame. Solids wont move. What Im trying to avoid is installing the UMI mounts and waisting a weekend putting the motor in only to find out it doesnt work. Im running a UMI RR k member so I assume like the factory one it isnt symetric hence the different mounts on either side to center the motor. Thanks for any info.

five7kid

iTrader: (14)

You said "kit", so I assume you mean the one that includes both engine side and chassis side.

Call me simple (or cheap - that fits, too), but you'll get solid mounts just using the K-member side with the factory clamshells.

Maybe I'm missing something.

IROCZ1989

iTrader: (1)

Idk. Its a kit. Clamshells and k member mounts. All powder coated black. My engine bay has been painted. My k member is powdercoated. Just wanted to get these personal preference. But I feel the install and application info on these are wrong. Just trying to get clarification.

five7kid

iTrader: (14)

I don't know the answer to your basic question about how an aftermarket product could be a replacement for a factory setup that is side-specific and the aftermarket version isn't side-specific.

It appears your options are:
1) Trust UMI that their products, when used together, will provide satisfactory results.
2) Powdercoat your factory clamshells.

IROCZ1989

iTrader: (1)

Or UMI could respond here and tell us why the factory is side specific and tell us their product is along those lines. My factory clamshells are already powdercoated anyway but its not the point. Maybe we are not on the same page on this. I know my options. I know whats out there in terms of mounts. Moroso,UMI,Energy sus, etc. I like the UMI setup, that is why Im asking. I want them to clarify here, or someone who has purchased these that they do work. Morosos are side specific. As is factory. Im sure you are aware of this as are many here. Im wondering if UMI are. Im using their k member. Its supposed to mirror the factory one which is non symetric. Just want clarification. It would be one thing for a bolt on piece not to work and be easily removed if it doesnt. If this is incorrect the whole drivetrain has to come back out. Something I can avoid.

five7kid

iTrader: (14)

I suppose you could PM "UMI Performance" and ask them to respond here. As far as I know I can't tag them on this thread so they get a ping about their name being mentioned. Their status right now is "Offline". Email in their TGO info is ryan@umiperformance.com.

UMI Performance

Unless our Iroc has two of the same side our factory motor mounts on our 1987 Camaro with a 305 TPI are the same side to side, which is where we got our dimensions. We have sold a lot of sets with no issues and our car currently is on them.

You could always put spacers under the solid mount where it bolts to the k-member if that helps.

But correctly, ours are not side specific based on the statement I said above.

I hope that helps

IROCZ1989

iTrader: (1)

It could be 86 isnt side specific. The rr k member is based of what year k member? I know the factory is not symmetric. And the side specific centers the motor.

UMI Performance

The K-member was built off a few different years. The pads for motor mounts match the factory pads.

Orr89RocZ

iTrader: (20)

I recall not being able to use umi solids on the umi kmember, simple would not line up. Even opening up the bolt holes, to get more movement to try to line up, never could get them to work.
Factory clams and polys worked fine so definately something going on there or i had a bad set of solid mounts. Dimensions must have been off

IROCZ1989

iTrader: (1)

This is what I dont want to get into. Buying a set of mounts and then wasting my time and it not fitting. I know the factory setup is side specific. I had mid 70s gm clamshells and the motor sat to one side and exhaust was up against the brake lines. On a small tube header you might not notice it. Alot of people do not know thirdgen clamshells are side specific. I think UMI does not know this either, or just dont want to acknowledge it. G body clamshells have a whole different number than the thirdgens. Thirdgens have two differnet numbers. I posted a picture. They obviously look different in height and size right to left. Even morosos solids are right and left specific. I know of only one other on here that said he had the same right and left. Earlier versions had a plate to offset the mount. Umi says never and issue and orr says his didn't even bolt up. I have a spare set. Umi willing to look at them?

Orr89RocZ

iTrader: (20)

I've had my hands on a half dozen sets of thirdgen motor mounts and clamshells and every one is side specific like the pic you posted.

It just was weird to me to not get the solids to work when the oem motor mounts with poly bushing did work. I had the oem block side clamshells on the correct side as i have always done and just no go. No idea why unless dimensionally the solids were off.

I dont recall if the kmember side mounts are side specific as well or not. I took them off the oem kmember and placed them on the side they came off for the tube k. Just to be safe

IROCZ1989

iTrader: (1)

Right. All the ones Ive seen are side specific. Umi makes a set off a car that had 2 of the same. Whats the chances of that? I know morosos are side specific. So why would moroso copy factory but these do not? I know its not cheap to make a diff mount for every car. But moroso makes the pads specifically for thirdgens. To me that means they are aware of the difference. Ive emailed UMI, many times and mentioned it. They just blow me off and say they work. Trying to support the board sponsors here. But I know for a fact g body mounts are not f body mounts. May be close enough to look ok. But when you have the actual right ones in there you will see there is a difference.

Orr89RocZ

iTrader: (20)

The mounts that bolt to the k member are side specific as well or no?

IROCZ1989

iTrader: (1)

No, on factory theye are the same. On the moroso setup though the mounts to the block are the same but the k member pads are side specific.

IROCZ1989

iTrader: (1)

So will UMI entertain me sending these spares I have to look at?

Orr89RocZ

iTrader: (20)

I did not realize the moroso stuff had both engine block side mounts and kmember mounts as a kit to work together

I simply tried to use oem block clamshells to mount to the umi kmember mounted solids. Did not work for me

UMI Performance

Maybe our car had G-Body mounts at one time? I don't think we are blowing you off, it's what we show and has worked so far for us. I am not saying it's right, we could be wrong but it is what we have right now. We will take some time as soon as we can to revisit these and see what we can find out.

As for the pad lower k-member solid mounts, # 0051. I am very confident in those being correct. We have made those for 10 years now just as they are. The discrepancy seems to be in the clamshell.

IROCZ1989

iTrader: (1)

For some reason Moroso switches it. All their sbc clamshells are the same. They sell the k member pad for sbc, but then they have specific thirdgen sbc k member pads. If you look at them in the pics they are a little different right to left. They take up the difference on the k member pads vs the clamshells like stock. And others here that have purchased them have confirmed they are marked specific right and left.

IROCZ1989

iTrader: (1)

So by looking at the pics their is about a 1/4 to 3/8 difference in height between the left and right. Umi says their stuff is correct. They advertise then as fitting 74-92 camaro. I had mid 70s mounts on this car before. Motor fits in, but it tilts towards pass side. Whatever. Ill just put the stock stuff back in. Umi doesnt seem interested at all to even look into it. Guess moroso, gm, and me are wrong then.

jmd

iTrader: (4)

This is possible; I've accidentally had a mix & match moment or two in the past.

I'll be honest, I'm watching this thread because I wondered how the Spohn LS engine mounts worked in the G-body if they happened to be side-specific frame-to-block height as the original F-body engine-side shells seems to be. I'm very much in info-gathering mode.

If the goal was to avoid the exhaust being too near floorboards, maybe the original engine mounts were an overall better option for NVH anyway.

IROCZ1989

iTrader: (1)

Funny you mention the stock mounts. I found a set of my original stock rubber ones out of the clamshell. Its definatly deformed at 65000 it was taken out. I also have a set of oem gm ones I bought last year. The es poly compared to the original gm and to the umi pads are basically all the same height, pad side as umi says 1.00 on their site. The difference is the clamshell. I even got ahold of my friend which has an 86 tpi and posed this to him. And yes he told me he tried to put the motor back in and found out he had the clamshell mounts on wrong side and motor was off. The umi ones say 74- but I had mid 70s clamshells on the car before. Its fits yes, you can get a motor in no problem. But when you swap out the clamshells to the right ones you will see how much different the motor sits. Im going to just use the poly mounts for now. I like UMI and have many of their products on my car and their customer service is second to none.But in this situation I have to say they are wrong in saying both sides are the same and interchangable to a g body.

TinnMann2

Just a little bit of info with my 305 to 350 swap, i have an 85 bird base. I was searching on motor mounts and found this thread. I just put my clamshells on the block and they are both labelled 334971. Its kind of hard to tell if they are different visually because they are on the block, but i could take them off and check them out if you think it will help you out?

IROCZ1989

iTrader: (1)

I have a set of those. They are a mid 70s clamshell I believe. Motor did not sit right with those unit. Be carful the motor will go in and look fine until you put headers on it and they lean to one side too much.

TinnMann2

Thanks for the heads up, I will watch for that. If things do not work out with these clamshells i should get a 14039436 for one of the sides? I have stock k member and new oem mounts and I figured I could re use the clamshells that were with the 305. Does this mean there was an engine swap sometime in my cars past if it does not have the correct clamshells?

You mentioned you have other UMI parts on your car IROCZ1989. Like what and how do you like them? I have sfc's from them and I am debating on upgrading my front end suspension and k member now that my engine is out... It wasnt the plan but it seems alot easier to do right now. One thing leads to another! haha

Drew

iTrader: (58)

By the book, there were three motor mount brackets used. 334970 or 334971 Left, and 14039436 Right. The 14039436 is consistent for the right side. Both 334970 or 334971 were used on the left side.

Of course the book isn't always 100% accurate.

IROCZ1989

iTrader: (1)

I think you will just need that part number ending 436 as the 70 and 71 are identical. I really like my UMI stuff. I have their RR k member and a arms and just purchased their rear panhard bar relocator with the drop in it for bigger exhaust. No complaints at all. They make top notch stuff. But on these clamshells they are off. I may be wrong and maybe they year they modeled them off the k member is diff from mine or the block as those were only 305s. Dont know. But if you look at the diagrams they list both clamshells as identical height which the correct parts numbers if you measure them are not. The pads on the k member are correct height though.