455 Engine Swap Question

jgmilberg

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I have a 1970 Cutlass that had a 350 Rocket engine in it, I am putting in a 455 and am having trouble getting the engine to rest correclty on the frame mounts. I have just ordered replacment rubber mounts for the engine because the ones that cam with it were bent, and cracked. I have the frame mounts that the bolt goes through, from front to back, not the style that bolts right to the cross member. Do I need to change the frame mount to get this motor to drop in, or should the new rubber mounts do the trick?
 

jgmilberg

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Anyone heard of matching 350 engine mounts with 350 frame mounts when installing a 455? I know the engine mount bolt spacing are the same from 350 to 455, but the 455 mounts are taller than 350 ones.
 

seamus449

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Engine mounts for 455

I haven't installed my 455 into my 65 Cutlass yet, and I am still worried about what engine mounts work best. I know there are two different types: one has a stud that bolts directly to the frame, the other has a horizontal bolt that goes through a separate frame mount. I think the stud kind puts the engine low, and the bolt kind puts the engine a little higher. I'm worried about clearance for oil pan, headers, hood, steering shaft, and power brake booster. I have also read that frame sag may be a problem. Any advice is appreciated, thanks.
 

Yogi442

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I have swapped out a few and have had to match the engine mounts to the frame mount design. As example I have a 70 455 from a Delta 88 that I have installed in my 76 Buick Century wagon, the mounts on the motor were designed to run directly through the cradle instead of from frnt to rear. I replaced the engine mounts by using a set from 76 455 and it bolted right up. You could try this method to save time on replacing the frame mounts.
 

joe_padavano

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You MUST use the rubber motor mounts and the metal frame mounts as a matched set, by both year and engine. 350 frame mounts and 350 motor mounts or 455 frame mounts and 455 motor mounts. The result is the same in either case, but you CANNOT mix and match. Prior to 1969, big blocks and small blocks used the same motor and frame mounts, but some vendors incorrectly sell the 69-72 big block mounts as 1968 also, which won't work.
 

joe_padavano

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I have swapped out a few and have had to match the engine mounts to the frame mount design. As example I have a 70 455 from a Delta 88 that I have installed in my 76 Buick Century wagon, the mounts on the motor were designed to run directly through the cradle instead of from frnt to rear. I replaced the engine mounts by using a set from 76 455 and it bolted right up. You could try this method to save time on replacing the frame mounts.
Big car motor mounts are COMPLETELY different from A-body mounts and are not interchangeable. The big cars use mounts with studs. The A-body cars use mounts with a cross bolt.
 

Yogi442

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Joe, thanks for clarifying. I was looking at this in reference to a mid size Cutlass/Century swap where the only difference was the engine mounts were different as the motor came out a a full sized vehicle. In my case I used a set of 76 Olds engine mounts so in turn I did match the frame and motor mounts to the same year which did work.
Joe, where are you located? I noticed that is says northern Virginia. I have family in Herndon and Suffolk. Are you anywhere near those areas. Sister and family are in Suffolk and love it out there. I was out few years ago and enjoyed the area.
 
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Marshtonk

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ok quick question where can i find both frame and motor side mounts im having trouble finding them sorry if this was an old post
 
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