Square vs. round motor mounts with a SBC

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Dec 28, 2006
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I think I finally figured out I reused the stock motor mounts when I converted it to a SBC. (Thanks who ever posted a picture of the stock mounts). For some reason, I can't remember what I used back then.

Anyway, I see the updated stock mount is square. Are there any issues with it as a replacement with the conversion?

Mine's made April '76.

TIA
 

65swb45

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As long as you don't have a steering shaft in the viscinity you should be fine.
 
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I used 4 rear "donut" mounts and 1/2" bolts that go all the way through. I wouldn't trust stock vulcanized mounts to manage 400 ft/lbs of torque and a flexible frame.
 
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I agree the bolt thru donuts are safer since they are caged and the old rounds ones aren't (one of mine is almost completely sheered).

The replacement square ones do look caged, is that correct?

Edit to add: I would seem to me that bolt thru's have to transmit more vibration than a pure rubberized mount.
 

reddingcruiser

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I used 4 rear "donut" mounts and 1/2" bolts that go all the way through. I wouldn't trust stock vulcanized mounts to manage 400 ft/lbs of torque and a flexible frame.
Yep, use the through - bolted variety. I had the vulcanized ones come apart once and had to finish the trail with a come-a-long holding down the left side of the engine. I use the ones AA sells and never had an issue with vibration.
 
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Never had a problem with vibration... the cage won't prevent the rubber from letting go and the mount lifting straight up. :D
 

Downey

 
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Hard to buy any motor mount now days that isn't made in India, and we've had both round and square separate- - -they are cheap, pack a spare???
 
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The old school method of using uncaged mounts is a couple loose links of chain spanning the mount to keep the beast within from destroying the hood. I'll buy a couple of the new ones and give them a try.
 
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Mount-ains out of mole hills, that's my style. There is little difference in the mounts except for the shape. The height is about the same and I don't see any interference anywhere. The country of manufacture is Japan so hopefully they won't separate the first time I tickle the secondaries.


 

RAYJON

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Look at the big block dodge/ first gen cummins mounts, pin is ofset but they are a big chunk of rubber about twice as big as the chevy ones, and they have a limiter to keep from tearing them apart, same problem made in india and the quality really varies but they were like 10$ each last time i bought some...
 
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