Are motor mounts specific to side?

[airman]

I am installing a new rebuilt 351W and AOD Trans. Right now as it sits the motor rear of the motor leans to the driver side. I will have to move about an inch at the trans output to line up the crossmember correctly. It even looks off. Could I have put the motor mounts on the wrong side? I believe they are identical. Is this twist normal?

 

[DirtDonk]

I believe they are the same. Are you saying that the motor is twisted, so that at the far end (of the transmission) it's offset to one side? Or is it twisted as in "rotated" so that the trans mounts do not sit square with the crossmember?
Since the motor mount tower holes are slotted to ease installation, an engine can actually be twisted inside the towers. I've run into it before on multiple occasions.

One time we noticed the passenger side header hitting the frame where it should not. After looking at things for a minute we realized the engine was tilted (rotated in the towers, not crooked sideways-like). Or from an aero perspective, the engine had "roll" on it, but not "yaw" if that makes sense.

Fixing it was as easy as loosening the engine mounts (transmission was not hard mounted yet) and two of us sitting on the fenders and each grabbing a header. Add a little lift-and-separate and we rotated the engine in the towers to a more neutral position. Luckily for our work the headers then fit better on both sides and no more interference on the passenger side.
So it can be done if it's "roll" but not sure what it would take to correct "yaw" in the mounts. Maybe some defective mounts? Would not surprise me at all considering the state of modern auto parts.

Paul

 

[Broncobowsher]

Slotted holes in the frame. Allow the engine to be bolted in with some roll to it.

Mounts are the same regardless of side. But some are taller than others. If you are mixing different mounts (not a pair of the same) that can put a roll in the engine as well.

 

[airman]

Its not rolling, its pointing towards the rear driver wheel by 2-3 deg. I have the mounts loose and I can move it but it seems like it will be pulling on the mounts. The mounts came together and didn't seem different. Just making sure before I start locking everything down. It would be hard to believe that the block had different mount holes than my last 351W. I'll pick it up a little when the crossmember is bolted and see if it doesnt settle in better. Thanks guys.

 

[Rustytruck]

loosen the motor mounts take off the mounts at the Transfer case adapter take out the fan and the radiator. grab the transfer case and shove it in a circle up and around now you should be able to settle it where you want it. it will move as much as space allows. transfer case is very close to the drivers side frame.

 

[Steve83]

Are you sure the frame isn't diamonded? The mounts are certainly identical & interchangeable; and the trans mount holds the powertrain inline. It all SHOULD be 1" off the centerline of the frame, to the right side. Study these diagrams:

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(click this text)

 

[airman]

Update: I was able to pry from the adapter end and get the crossmember mounted and bolted. Its centered now and I suspect that when I take these motor mounts out years from now they will be as Dirtdonk described and one will seem different. Thanks for the responses