351c motor frame mounts

Spike Morelli · Mar 26, 2023

rackerm said:
Unfortunately, Hemikiller is correct as always. When I spoke a few months ago with "thee" guy at Mustang etc. He said they were working on getting the rubber insulator for the 73 verts. He seem hopeful that it would happen but he offered no timetable as to when. If you can use a pair of 71-72 or 73 vert or hardtop frame mounts, I have a collection of them. I would be interested in your 73 Vert mounts.

Hey rackerm, with whom did you speak to at Mustangs ETC? I used to work there many years ago, and at that time, the original owner of the place, Arnold Marks, had passed, and his son, Garrett was soldiering on with the place. Just wondering if Garrett was the guy you talked to.......

351c1971 · Mar 27, 2023

Good point. The motor frame bolts are subjected to both shear and tension. Grade 8 hardware is always a good idea here as well.

Steve1973M1 · Mar 27, 2023

Hi all,
I had a 1971 mustang that I raced and had Lakewood muscle motor mounts. They failed because they had a bolt through motor mount which after many drag race launches the drivers side failed. You had to cut a hole in frame mount as well. What happened when the bolt failed was the mount then ripped apart and the engine torqued up, which then the engine twist, pushed against shift rods causing car not to shift to 3rd gear unless to you let off gas or kill the ignition. The 1973 mounts are the best design! They are like all modern ford designs (my 1998 mustang has same design) in which if rubber fails they still do not allow engine to lift away from frame. I remember an old buick with mechanical throttle linkage and drivers side motor mount failed. The car would accelerate and the only way to stop this 430 cubic inch monster was to turn the key off.

INPete · Apr 27, 2023

I'm also in this same dilemma with my 73 vert. I've started a new engine build and would like to upgrade the engine mounts, but can't seem to figure out what combination(s) I will need if I want to use the Prothane mounts. I did see these available on NPD, but would like to see if anyone has any feedback if they will work on the 73 vert. The listing shows it will work on 65-72 and are adjustable. In the vehicle information section, there is a note that says "73 is very different".

https://www.npdlink.com/product/mot...2Bmount&top_parent=200001&year=1972&year=1972

Hemikiller · Apr 27, 2023

INPete said:
I'm also in this same dilemma with my 73 vert. I've started a new engine build and would like to upgrade the engine mounts, but can't seem to figure out what combination(s) I will need if I want to use the Prothane mounts. I did see these available on NPD, but would like to see if anyone has any feedback if they will work on the 73 vert. The listing shows it will work on 65-72 and are adjustable. In the vehicle information section, there is a note that says "73 is very different".

https://www.npdlink.com/product/mot...2Bmount&top_parent=200001&year=1972&year=1972

Those absolutely will not work on a 71-73, they're for the 65-70 cars. Those cars have a bolt on frame bracket like below, and the RMP mount replaces that and the insulator.

The simplest remedy is a 71-72 coupe/sportsroof frame stand and either a set of Anchor 2257 insulators or the Prothane mounts you want to use.

@Rick@NPD might want to correct that listing. They're also not going to work with the 65-71 intermediates

INPete · Apr 27, 2023

Hemikiller said:
The simplest remedy is a 71-72 coupe/sportsroof frame stand and either a set of Anchor 2257 insulators or the Prothane mounts you want to use.

Thanks for the heads up on the NPD adjustable mounts and the simple remedy. A quick question on the frame stands, would it also be ok to use the 71-72 vert/big block along with the Anchor 2257's? Looking at the pics of the two different frame stands, I notice there is a slight difference in angle. Didn't know if that would cause any vibration issues in my 73 vert.

Hemikiller · Apr 28, 2023

INPete said:
Thanks for the heads up on the NPD adjustable mounts and the simple remedy. A quick question on the frame stands, would it also be ok to use the 71-72 vert/big block along with the Anchor 2257's? Looking at the pics of the two different frame stands, I notice there is a slight difference in angle. Didn't know if that would cause any vibration issues in my 73 vert.

No, those won't match up properly.

rackerm · Apr 28, 2023

INPete said:
I'm also in this same dilemma with my 73 vert. I've started a new engine build and would like to upgrade the engine mounts, but can't seem to figure out what combination(s) I will need if I want to use the Prothane mounts. I did see these available on NPD, but would like to see if anyone has any feedback if they will work on the 73 vert. The listing shows it will work on 65-72 and are adjustable. In the vehicle information section, there is a note that says "73 is very different".

https://www.npdlink.com/product/mot...2Bmount&top_parent=200001&year=1972&year=1972

The prothane captive-style mounts are designed like the 73 captive motor mounts, but for a 71 or 72 frame mount. You can use them with your 73 vert if you also use the 71-72 vert/big block frame mounts. The prothane will not work with the 73 frame mounts hardtop or vert. The only motor mounts that work with the 1973 D3ZZ-6028-B or a D3ZZ-6029-A frame mount is 1973 captive-style motor mounts (D3ZZ-6038- X which went through 8 engineering revisions before the dust settled. The rubber insulator in side the captive motor mount also carried a part number, for example, D3A-6038-BD). What makes even more confusing is the active motor mount rubber insualtor is different between hardtop and convertible. This difference is enough that a company that rebuilds 73 motor mounts can only do Hardtop mounts, they cannot rebuild 73 convertible mounts.

Any Ford motor mount having a Ford interchange part number older than D3 is most likely not compatible with the 73 frame mounts.

I heard of folks shimming the 73 frame mounts up (I don't know how much), so they sit taller like the 71-72 frame mounts and then using a 71-72 style motor mount.

I have a set of 71-72 vert/big block frame mounts I could sell, if you decide to go that direction.

INPete · Apr 28, 2023

I'll keep those in mind. I have found a set of 71-72 hardtop brackets that I'm working a deal on at the moment.

rackerm · Apr 29, 2023

INPete said:
I'll keep those in mind. I have found a set of 71-72 hardtop brackets that I'm working a deal on at the moment.

They are slightly shorter and have a different angle than the convertible brackets, if you shim the bottom two bolts about a 1/8" to 1/4" you can raise them as tall as the convertible frame mounts and give them more angle like the vert mounts, that should work with the Protane active motor mounts. Good luck. Please let me know, iIf they do work for you. Also if your current deal falls thru, I have a set of 71-72 HD mounts as well.

will e · Apr 27, 2024

Edit: Looking at pictures of Motor Mounts these do not have the 4 things that look like rivets. They look like 71/72 mounts but I have no idea why I would have them since I never owned a 71/72.

While Cleaning out the attic I found what I believe is a set of used 73 convertible mounts. The only identifying marks are 2286 molded into the rubber and "Made in India". It's possible they were for my 73 Mach I but that means I held onto them for 40 years which seems unlikely. I am not sure I had the smarts to keep old parts when I was that young. Certainly not OEM and it's possible they are aftermarket for hardtops. The engine was replaced before I got the car so someone might have used hardtop mounts? I am digging through some of the old threads trying to determine if I can identify them. They are still 'solid' but I don't think I would use them. Certainly am not going to toss them in the garbage, perhaps one day new insulators will be available? Any input you guys have on identifying them would be appreciated.

Steve McMahan · Apr 27, 2024

Post pics of them

California 72 · Nov 18, 2024

Good afternoon all.
The last couple hours I’ve been bouncing thru the posts here and elsewhere for an understanding about the vert mounts.
My head has hit every wall in every post because of too many variables listed. I understand it’s on my end seeing as I’m stuck reading on a phone so,
If ya’ll would please help as I ask for what exactly is needed for this part of my project
72 convertible
351c
4v
Stock 4v manifolds

For a simply basic, lower engine position and non urethane type;

What perch is needed?

What insulator is needed.

Any modifications?

Hemikiller · Nov 18, 2024

71-72 hardtop/sportsroof frame stands with two Anchor 2257 mounts

midlife · Nov 18, 2024

He's asking about convertible motor mounts.

Hemikiller · Nov 19, 2024

midlife said:
He's asking about convertible motor mounts.

The problem is the convertible mounts aren't available. *Supposedly* Dan at The Mustang Barn can make a set of the correct convertible mounts, but 've yet to see anyone actually purchase and use them.

Least frustrating solution is to swap to the non-vert parts.

Stanglover · Nov 19, 2024

Hemikiller said:
The problem is the convertible mounts aren't available. *Supposedly* Dan at The Mustang Barn can make a set of the correct convertible mounts, but 've yet to see anyone actually purchase and use them.

Least frustrating solution is to swap to the non-vert parts.

Just a curiosity question from someone unfamiliar with verts; Why are vert mounts different to any other 71-72?
I know 73's are different, but why would the motor in a 71-72 vert need to be set in a different position?

351c1971 · Nov 19, 2024

My guess this is to clear the trans tunnel reinforcement plate which is used only on the convertibles.

AcesArneson · Nov 19, 2024

Not sure how much this will help you but I have a '73 Vert and went through the motor mount nightmare you are currently navigating. My original mounts were worn out and there is no direct replacement so I followed the directives of Q1SVT and drilled apart the rivets to rebuild from my old '73 Vert mount. Once it is all bolted together there is a slight difference in angle from the mount to the pad that has to be adjusted. I used a 1/8" washer on the top two bolt holes on both sides and they lined up about 95% which was good enough to get the connecting bolt in if you hold your tongue right. I was tempted to put the washer in the clamshell of the mount but I thought it might allow the mounts to slide around if they were not tight enough. Good luck with your project.

AcesArneson said:
Looks like the '73 Verts were definitely lowered while trying to eliminate a vibration issue. The pads for the non-convertibles are much taller, looks like at least 3/4". I followed your advice and picked up a set of Westar EM-2370's and drilled out the rivets on them as well as the rivets on my original '73 Vert motor mounts and flipped the pad from the 2370's into my original clamshell. I roughed them in the other day to see how they would fit and it is perfect! I just need to go pick up some grade 8 bolts the proper size and I am off to the races.
Final question; there seems to be a lot of room in there with the new rubber. The old rubber was stuck to the inside of the clamshell pretty good and I had to chisel it then wire-wheel off the residual (what a stinky mess). The new rubber has a groove in one side so I am assuming that groove is a locator for where to set the rubber before clamping down on the clamshell. Is that what you recall, or can you simply glue and install? Any recommendation on the type of glue to use to bond the rubber to the mount so it doesn't slip around under operation?

On a side note, It was way easier to install the headers when I pulled off the motor mounts. This is just a test fit and I have work to do on both the mounts and the headers so I will either be lifting the engine/and trans again or pulling them again to finish off the work. Sounds like a lot of work but it's way easier than trying to contort your hands and fingers to get the header bolts tight enough.

Cleveland Crush · Nov 19, 2024

AcesArneson said:
Not sure how much this will help you but I have a '73 Vert and went through the motor mount nightmare you are currently navigating. My original mounts were worn out and there is no direct replacement so I followed the directives of Q1SVT and drilled apart the rivets to rebuild from my old '73 Vert mount. Once it is all bolted together there is a slight difference in angle from the mount to the pad that has to be adjusted. I used a 1/8" washer on the top two bolt holes on both sides and they lined up about 95% which was good enough to get the connecting bolt in if you hold your tongue right. I was tempted to put the washer in the clamshell of the mount but I thought it might allow the mounts to slide around if they were not tight enough. Good luck with your project.

Nice job on the mounts Aces. FWIW you may want to consider a taper washer (wedge washer) instead of the flat style:

351c motor frame mounts

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