Engine Annoying motor mount question (vert or poly) clearance concerns.


Active Member
Aug 7, 2017
Hello all,

I hate to ask these questions which I know have been asked and answered a million times BUT here I am:

I have a 25th anniversary 90 GT. (technically 89 and 1/2 I think) and I am doing a motor and trans swap on it. It's getting a DSS built 306 and with a built C4.

I am in need of motor and transmission mounts and I have a couple questions.

1. Are the convertible mounts ACTUALLY shorter than the factory hatchback mounts? After much research on this and other forums I think i am more confused. Some say they are shorter but they don't fit on a hatch k-member. Some say they drop right in and work perfectly. Some say they fit fine but are trash quality. The motor mounts I pulled off the car were both original and completely broken so I don't want to give myself new clearance issues if I can avoid it.

I am running a pretty stout 306 with a built bottom end, trick flow heads, an X303 cam and an explorer intake, so my next question would be...

2. Should I even bother to run a stock motor mount or should I go with something like an energy suspension or a prothane? The car will mostly be a street car but not a daily driver. It will make a few "just for fun" passes at the local drag strip, but wont be in any serious competition racing. I don't think will mind the extra vibrations and I obviously want the car to preform well, so I am leaning this direction anyways.

The reason I am concerned is I would REALLY like to use my factory hood for now, and I know I am going to lose some clearance already with the explorer manifold. I am also running shorty headers so I am wondering about clearance with the steering shaft. What has worked well for you guys?

3. Trans mounts and motor mounts should all be the same material, correct?

Thanks for your time and knowledge

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