Question about motor mount modification - Pontiac GTO Forum
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post #1 of 5 (permalink) Old 10-07-2018, 07:50 PM Thread Starter
 
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Question about motor mount modification

I recently installed a 400 in my 65 4 spd goat. I installed cast iron headers and have an issue with clearance between the drivers side header and the rag joint. The rag joint studs are rubbing the bolt head on the front of the header. I am thinking of cutting a 1/4 inch steel plate to place under the frame half of the motor mounts. I would cut this to match the frame mount and drill to bolt directly under the mount. Will raising the engine 1/4 inch effect the drive line in any way, such as creating a vibration?
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post #2 of 5 (permalink) Old 10-07-2018, 09:03 PM
 
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Don't see how only a 1/4" change could cause any problems.
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post #3 of 5 (permalink) Old 10-08-2018, 10:07 AM Thread Starter
 
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Thanks big D. In looking through past threads I read a comment that there can be sag over time that draws the front frame rails together thus lowering the engine which could be the culprit in my case. In any case I am going ahead with installing at least 1/4 " plates to lift the engine.
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post #4 of 5 (permalink) Old 10-08-2018, 12:40 PM
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It's possible that it might throw the u-joint angles off and introduce a vibration, but 1/4" near the front of the engine is a pretty small change. If that happens, I recommend installing adjustable upper rear control arms to enable bringing things back into alignment.

For your reference, the image below shows proper alignment if you're not already familiar with it.

Bear
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post #5 of 5 (permalink) Old 10-09-2018, 09:48 AM Thread Starter
 
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Very helpful information. Thanks BearGFR!
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion

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