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Discussion Starter · #1 ·
I need to replace the old motor mounts and no nothing about them. I need a set for a 454 in my vette. Do the 350 / 454 engines use the same mounts? I have looked and found mounts any where from $10 up, are there different styles of mounts?
Someone please educate me.:huh: Thanks Mark
 

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The 350 and 454 mounting bolt pattern are the same. But the 454 had heavy mounts than the 350. They are made so they can not pull apart from more torque...Just order mounts for a 454 and you will be ok...
 

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Discussion Starter · #3 ·
Ok need some help here. I know motor mounts are not rocket science but heres the problem. Checked auto parts stores and even summit and jegs. They say bb and small block are the same.
I would really like to get the right ones for a big block can someone point me in the right direction. Also what years (BB) will fit my 76, a link would help :cheers: Mark
 

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I don't know anything about BBC mounts being stronger than SBC mounts, but I know if strength is what you're looking for here is the pecking order.

Stock (Rubber)
Poly
Solid

They all have their purpose.

The stock rubber mounts handle engine vibrations the best but under heavy stress they give out first.

The poly mounts are stronger and give a lot less, stiffening up everything a bit, but you feel more of the engine vibrations.

Call me crazy but I prefer the solid mounts. They won't break or wear out. Ever. They stiffen up the frame...essentially turning the engine into a big cross member, which equals less frame flex when driving in the twisties. Finally, yes, you feel engine vibrations, but my car is gonna vibrate regardless of the engine mounts.
 

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I have solids on my 427, you never have to worry about the mount failing, does it vibrate more than if it had been rubber or poly, yes but it isnt that much of a difference.
 

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Call me crazy but I prefer the solid mounts. They won't break or wear out. Ever.
There was one guy on this forum who claimed that one of his solid motor mounts broke in half. Don`t remember if he provided pictures or not but I don`t think the engine was that modified.
 

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I have polyurethane on a healthy 427 with an L88 hood. Can't say I'm aware of any intrusive vibrations worth noting. I get on the engine pretty hard and you can see through the hood opening at the back that the motor does not move. The sidepipes could be a contributing factor to that.

Not much help. I'll say I would buy them again.
 

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There was one guy on this forum who claimed that one of his solid motor mounts broke in half. Don`t remember if he provided pictures or not but I don`t think the engine was that modified.

I guess it's possible but highly and extremely unlikely.

Go to a parts store and hold a set. Then you tell me what you think. They're one piece and VERY thick. :thumbsup:
 

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I guess it's possible but highly and extremely unlikely.

Go to a parts store and hold a set. Then you tell me what you think. They're one piece and VERY thick. :thumbsup:
And they look totally BADASS when installed!!:thumbsup: Clean, Shiny, no mass of rubber getting in the way of viewing the block. I've installed them my L-82, but haven't fired it up yet, however, I don't care about a little extra vibration, I just want the added security of solids and the enhanced frame stiffness they add!:partyon:
 

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I would never put solids in a street car, poly is FAR superior and totally able to restrain a 450hp engine. Energy suspension has very hard polys, prothane is a lot softer.

If you go solid be sure to use a solid tranny mount to so you don't break the tranny case.

The lower mounts are the same bbc versus sbc. BBC upper clamshells are usually taller but in some cars you can use small block clamshells without crossmember interference.

good luck
 

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This is good info fellas. Sounds like I will be doing solids:thumbsup:
I think there's 2 different results from vibration to be considered. One is what you feel, maybe some vibes through the steering wheel and through the shifter. And the other would be what you hear, like the knobs on the radio, loose change in the ashtray and the steering wheel horn button buzzing. I think the second type would be the most annoying.

At what horsepower/torque level should someone really consider solid mounts as a necessity?
 

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At what horsepower/torque level should someone really consider solid mounts as a necessity?

I think that all depends on how you drive. I've seen a 300 HP crate engine tear up a set of rubber mounts within weeks of being installed because the driver was very rough in his driving style.

I have also seen torque monster big blocks last decades on stock mounts because the drive train wasn't abused.

If you have an aggressive driving style, I would recommend poly or solid mounts at or above 300 HP. If extra stiffness is a plus for you, I would also recommend poly or solid mounts...and a spreader bar.
 

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I think that all depends on how you drive. I've seen a 300 HP crate engine tear up a set of rubber mounts within weeks of being installed because the driver was very rough in his driving style.

Those mounts were defective or pre-damaged or coupled with a bad transmission mount.

They're not sexy but a quality rubber mount will take everything you can throw at it with street tires unless there are other issues with the engine/tranny mount system.

I run prothane polys in a blown, stick shifted elcamino that's flogged mercilessly with locked, 4.56 geared drag radials. 6 years and 20K miles later (prolly 250 1/4 mile passes) they are just as tight as new. Just about the only thing on the car that hasn't broken.

Having lived with solids on the street before polys became available, I'm done buying solids for anything with license plates.

Here's the unspoken reality of solid mounts......if you need solid mounts then your car makes so much power it also needs a rollcage to reinforce the chassis. Because the engine/trans unit isn't anywhere near as flexy as your stock frame. So if you bolt them together rigidly and beat the snot out of it, the engine/trans sees way more twisting/bending force than it appreciates. Yes, some people get away with it. Others suffer failures they never really link to the mount system. A transmission is not a frame crossmember but solids turn it into one. (ever smack a trans case with a sledge? They're THIN)
 

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Here's the unspoken reality of solid mounts......if you need solid mounts then your car makes so much power it also needs a rollcage to reinforce the chassis. Because the engine/trans unit isn't anywhere near as flexy as your stock frame. So if you bolt them together rigidly and beat the snot out of it, the engine/trans sees way more twisting/bending force than it appreciates. Yes, some people get away with it. Others suffer failures they never really link to the mount system. A transmission is not a frame crossmember but solids turn it into one. (ever smack a trans case with a sledge? They're THIN)

Good point Todd. This is why I always use rubber transmission mounts with solid engine mounts.

The engine helps stiffen the from, and the rubber transmission mount absorbs the flex as the engine and frame move as one.
 

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Good point Todd. This is why I always use rubber transmission mounts with solid engine mounts.

The engine helps stiffen the from, and the rubber transmission mount absorbs the flex as the engine and frame move as one.
Oh man, never do that. Gotta use all three positions as a matched set, or the weakest mount takes focused stress. I've split th350s around the bellhousing learning this lesson.
 

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Oh man, never do that. Gotta use all three positions as a matched set, or the weakest mount takes focused stress. I've split th350s around the bellhousing learning this lesson.
I was under the impression, (based upon my research prior to buying the solid motor mounts), that a good combination was solid motor mounts, with a poly tranny mount, (which is what I did). This is the first time I've ever heard about using a solid tranny mount with solid motor mounts.

Just how hard do you drive your Vette?
 

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Solids with a poly trans mount may work out better as the poly is firm. But that particular combination is something I've never tried. Poly mounts have made solids obsolete for anything other than a true race car.

The whole point of a solid mount is the car's abused too much for a stock mount. So if the question is how much do I beat my cars, the answer is more than people who think they need solids! :devil:
 

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Oh man, never do that. Gotta use all three positions as a matched set, or the weakest mount takes focused stress. I've split th350s around the bellhousing learning this lesson.

Isn't that the point? Making the transmission mount the mount that takes the flexing? It breaks before the transmission case if I decide to drive extremely rough?
 
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