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Doc76
06-07-2025, 03:37 PM
Hey guys
I tried recently to swap my motor mounts from stock rubber to Energy Suspension to take some flex out of the motor under heavy load.
Pipes were hitting the body. I was able to cut away the body on the DS to remedy that however noticed the pipe support under the car would touch the body under hard acceleration. So next step was to swap to the ES engine mounts.

Bought the correct ES kit including tranny mount. (Good thing I did because I suspect the OB used a used rubber tranny mount and it was nearly broken). For the record I did purchase the recommended ES mounts. I was lead to believe that when I do swap to my BP347 I can reuse my BBK 4-into-4 headers so having a bit of time, thought I’d confirm the mounts would work out.
Confirmed with BP that my 347 would sit in the same spot and headers also would sit in the stock location.
All that was left was to throw the ES mounts in and confirm that.
In doing so I noticed once installed they had raised the motor enough to misalign the side pipe flange to an unusable point. Lifting the motor inadvertently swung the header flange forward a lot. Took them out and side by side appear to be ~5/16” higher than stock rubber.
I don’t see much on this issue on the forum.
I asked FFR for input and they said I may have to purchase their newer ball flange SS headers. I understand it’s debatable whether the FFR ball flange style headers are a good option, the unexpected cost and no shortage of cracking issues on those SS headers, I’m hoping there’s a simpler option.

My initial thought was to oblong the holes on the ES mounts to allow the mounts to move inboard, dropping the engine back down and thus shifting the header flange-to-side pipe connection back into place but…..not sure if that’s a good approach or if I can get enough slot to make it all work out. Before I “wreck” a good set of ES mounts, thought I’d ask.
Also not sure if one would consider shimming the tranny mount to gain more movement understanding this would affect pinion angle.

Any advice would be appreciated

Fman
06-07-2025, 07:27 PM
You can run fixed mounts and this will lower the engine approx 1/2-3/4". I have been using them since I built my car 4 years ago, 7600 miles now on them and zero problems. I also have had no issues with headers/flanges cracking.

David Williamson
06-08-2025, 06:53 AM
If I remember correctly. Back on early builds guys were using Mustang convertable engine mounts because they were slightly stiffer and lower, maybe that is what you have. The poly ones you got should have been a direct replacement. I did that change when I built my Mkll, with the stock mounts the engine moved too much. Other than that sorry not much help.
David W

Doc76
06-08-2025, 11:43 AM
You can run fixed mounts and this will lower the engine approx 1/2-3/4". I have been using them since I built my car 4 years ago, 7600 miles now on them and zero problems. I also have had no issues with headers/flanges cracking.

Are these a custom item or do you happen to know if someone carries them?
Thx

Doc76
06-08-2025, 11:56 AM
If I remember correctly. Back on early builds guys were using Mustang convertable engine mounts because they were slightly stiffer and lower, maybe that is what you have. The poly ones you got should have been a direct replacement. I did that change when I built my Mkll, with the stock mounts the engine moved too much. Other than that sorry not much help.
David W

I was able to confirm with the OB the rubber mounts are convertible mounts. Not sure that’s accurate.

Derald Rice
06-08-2025, 01:46 PM
ES mounts are built to convertible dimensions.