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Discussion Starter #1
Scored a good deal for 66-70 shock tower engine brackets.
Just received new 2257 Anchor (private label).
Made in USA...Georgia!

Besides just swapping them out.
Winter is here until April-June, so I may not have the opportunity to test drive.
I didn’t have vibration issues with 65 mounts, hence the question.

Are there driveline angles that will need to be addressed?
What kind of torque/hp can these handle without modifications?
 

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The engine mounted at the same height regardless of the mount type (before or after 11/1/65).

The same mount was used in 66-72 Mustangs, for 289, 302, and 351. That includes the BOSS 302 and BOSS 351. Safety ears were added in 1970, to prevent the engine dropping through broken mounts.
 

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There has been much discussion about whether or not there is a difference in the height of the engine as it sits in the car depending upon whether it has the '65/early '66 mounts or the late '66 mounts. I forgot to measure when I swapped my mounts as required for header clearance.
If you are swapping mounts could you be so kind as to lay a straight edge across the fenders and then measure down to a particular point on the engine before and after swapping the mounts?
 

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If you don't have a problem with the early mounts I would wonder why you want to install the later mounts. I have always heard the later mounts would sit the engine higher but I have both and less than 1/4" diff. I ended up using the early mounts and there are no header issues with patriot tris
 

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Discussion Starter #6
There has been much discussion about whether or not there is a difference in the height of the engine as it sits in the car depending upon whether it has the '65/early '66 mounts or the late '66 mounts. I forgot to measure when I swapped my mounts as required for header clearance.
If you are swapping mounts could you be so kind as to lay a straight edge across the fenders and then measure down to a particular point on the engine before and after swapping the mounts?
Funny you mentioned this height difference.
That is primary reason for my question.

I didn’t have vibration issues with 65 mounts.
I did modify them with a couple of 3/8-16 bolts (each) to prevent separation, I do have some vibration from this modification.
No complaints.

Makes for an interesting ride when throttle linkage is binding at full throttle heading into the fence and neighbors car.

I had “heard”the same thing many years ago, as well as notes on some headers “use 66-70 mounts”.
I currently have long tube Hooker headers 6901’s on my 5.0.

I will definitely add before and after.
Then we can lay this “urban legend” to rest. 😂
 

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Discussion Starter #7
Total difference between 65 and 66-70 on my car is 1/8”.

Straight edge on fenders, just behind the distributor, front edge of shock mount on both sides.

I noticed a significant difference in clear area under the exhaust ports.
That might be why some headers may require the 66-70 mounts.
Not so much for shock tower clearance, just installation/removal reasons.

741841
 

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Discussion Starter #8
I’ll try pictures later, cell service around here is marginal.
I did have more, always something.🤪
 

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I have addressed this countless times. Manufacturing spec mounts all the same height 65-70. The 67-70 convertible sets the angle of the rubber differently, to counter a vibration on some cars at 35 mph. No difference in height.

The urban legend began when people forced hardtop mounts into convertibles, because they were sold the wrong part.

The header problem is due to the outside corners of the upper bracket on the 65 type, which sticks out more on the front corner of each side. My choice would be to get headers that fit better. 45 years ago I had Casler full-tube headers that fit perfectly with my early mounts, any headers that won't are simply poorly designed. We're talking about 1/4" here. Any manufacturer who forces you to buy different engine mounts over that is simply palming off a second-rate product.

How many threads are there here on header and tri-y fitment? Should be a whole unique forum. And yet, I once re-installed a set of original tri-ys on a 66 GT350. Went on easily with zero clearance problems, and no dents. In this day of laser measurement and computer-aided design, it's simply insane that companies sell products that don't fit, when 50 years ago, parts made by hand on assembly jigs did fit.
 

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Discussion Starter #11
22GT, I wasn’t aware of convertibles having different mounts either. Even big name header manufacturers have notes referring to mounts to use.
They really don’t specify why...Interference issues or ease of installing.


From under car, to install long tube headers, visually appears higher.
Perhaps this is where the “urban legend” started of being 3/4” higher.

I had experimented with raising engine up with washers between engine and mount a couple of years ago.
I was installing long tube headers at the time.
I actually had less clearance between header and tower.
Didn’t make sense to do that, back to stock configuration.

The 65 mounts were initially modified (3/8-16 bolts x2 per mount) when new.
Don’t recall age of them now...I think 2009.
They appear to have settled too.


“Knowing is half the battle....YO JOE”😂


https://i.ibb.co/Kxvt6bx/E9028890-0-E4-D-4057-AB1-B-D08-E9-D0-B2-AB9.jpg
https://i.ibb.co/sjcC5fm/ACC69-F84-DF5-E-4-B04-877-A-B95-A6-C0562-AE.jpg
 

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Discussion Starter #13
There has been much discussion about whether or not there is a difference in the height of the engine as it sits in the car depending upon whether it has the '65/early '66 mounts or the late '66 mounts. I forgot to measure when I swapped my mounts as required for header clearance.
If you are swapping mounts could you be so kind as to lay a straight edge across the fenders and then measure down to a particular point on the engine before and after swapping the mounts?
FYI, the 65 brackets (cast) are noticeably heavier than 66 mounts (welded steel).

I also recall reading about isolating vibration with 66 mounts.
 

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22GT, I wasn’t aware of convertibles having different mounts either. Even big name header manufacturers have notes referring to mounts to use.
They really don’t specify why...Interference issues or ease of installing.
I had it from a Ford engineer who was there that certain Mustangs had a vibration at 35 mph, I don't recall if it was a specific engine version or transmission. Ford fixed it by switching to a somewhat different insulator, Ford C7ZE, industry 2286. The rubber pad was the same, as was the bracket that attached to the mount, but the upper steel bracket (bonded to the pad) was different, as was the bracket bolted to the frame. The result was the pad mounted at a very different angle, eliminating the vibration. At the end of the 67 model year, Ford switched back to the 66 style insulator (C6OE/2257) probably because it was cheaper, being produced in vastly greater quantity, on most Mustangs, except for the convertible, which is where the problem had occurred. They continued to experiment, because the 1970 BOSS also had the convertible mount. This continued in 71-72, except of course the frame bracket was drastically changed. In 1973, the new federal regulation for motor mounts kicked in, and unique 73 insulators were introduced. The 73 convertible insulator is stunningly rare.

The Prothane mounts for Mustangs are virtually identical to the 73 non-convertible mount. Replace the bolts with rivets, paint them black, and it would be hard to tell the difference.


A curious side note, which may explain much. Probably to save a buck, the frame mounts for the 67 289 were the same as the frame mounts for the 67 390 (and 68-70 390/428). The non-convertible 68-70 required a new design frame bracket. All of that was probably due to the desire to shave a dollar or two off the price of the car. Times half a million cars, it does add up.
 

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Discussion Starter #15
I’m sure cost to weld brackets together was way cheaper than the use of a cast part. Especially time/labor consideration to make cast parts.
 

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Well, the stamped version had three parts, plus two steel parts on the insulator. The early insulator had that, plus the very heavy stamped L bracket, and the cast steel frame brackets. Not to mention the early K code brackets, which look like they were copied from tank parts.

For 67 they had the same frame brackets for the 289 and 390, pretty impressive.
 

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The only mount that was different than what has been discussed is the HiPo or K code , multi piece mount. When new , they start out at the same height as the standard mounts. But because of the multi piece design ( over tightening the "center bolt") and the double thickness rubber insulator , they suffer more from "crush" than a standard mount of either design. Since few have them , it's not often brought up.
Randy
 
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