455 Olds in place of 454 in 76 GMC (frame to engine mounts?)

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OldBlueDually

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Hi gents, I have a 76 GMC crew cab dually that "had" a 454 in it that was previously removed before I purchased it. My 1969 455 Olds Rocket will be going into this truck.

My question is, is there anything off the shelf I can buy for frame to engine mount? I have the motor mounts themselves already bolted on the engine. Curious to know if something works!

I will be using the stock TH400 trans that is in the truck, so the adapter plate & all the goodies are on the way to make it work. If I could purchase these frame to engine mounts that would be nice, I am just not sure if I can, and if I can.....what do I use?

If anything, will make some, but I would rather not.

Thanks!!
 

jjester6000

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I believe that trucks with the olds 350 diesel have the correct frame mounts for the 455.

I don't think they remake them though
 

Matt69olds

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I have a 455 in my 81 GMC, the truck was originally 350olds diesel powered. The 455 drops right in like it was meant to be there. Find the 350 Olds diesel mounts, if you have all the Olds accessory brackets you will be in good shape. If A/C is in the plan, your going to have to have hoses made. The bbc compressor is on the drivers side, Olds has them on the pass side.


I’m pretty sure the 69 455 will run circles around the 76bbc, and probably get better mileage. Even with the lousy 3.08 gears in the 81 it pulls great.
 

Salty Crusty

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Dang, I wish you were in Texas, I have a BOP TH-400 that I need to get rid of and you wouldn't need the adapters!
 

OldBlueDually

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Thanks for the reply’s on this guys!


Jjester….so those mounts cannot be purchased new? THIS would certainly make life a bit easier if I could buy them. I sent a note off to an old junkyard yesterday, I will see what they say about it.


Matt, I do have another 455 Olds with all the brackets on it I “believe” I need to run to my folks place & check it out to be sure, but I am fairly certain the stuff is on there. For now, I will leave the AC out of this truck, I just want to get it on the road and be safe….with heat if it gets chilly in the fall. This BBOlds I am using is a dang good running engine, and the Olds engines all around I feel had a deeper/throatier sound to them. Love my Oldsmobile’s!!


What other year trucks used that 350 Olds Diesel?


Salty, now that would make life easy!! Heck, I would have traded you if you needed this one! I used to have BOP TH350 on a 73 Olds Rocket 350 I built for my 80 Olds Delta88 two door…..


Anyhow, what fun would this be if it was just simple, right? o_O
 

OldBlueDually

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Guys, for those of you that know what that mount looks like, is this it? I selected 81 GMC with the 5.7 diesel and this is what it came up with.....if this is correct, I will get a couple on order.



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Bextreme04

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That looks like the standard SBC/BBC motor mount. I saw a post on another forum talking about napa having the right mounts. I think this might be the right ones: https://www.napaonline.com/en/p/BK_6021119?partTypeName=Engine+Mount&keywordInput=motor+mount

For some reason they say "Manual Transmission Mount", but they obviously are not. I've done a few other searches and those look like the olds motor mounts. My local napa had them in stock and they are only $8 a piece, so I'd say it's worth a try at least.
 

OldBlueDually

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That looks like the standard SBC/BBC motor mount. I saw a post on another forum talking about napa having the right mounts. I think this might be the right ones: https://www.napaonline.com/en/p/BK_6021119?partTypeName=Engine+Mount&keywordInput=motor+mount

For some reason they say "Manual Transmission Mount", but they obviously are not. I've done a few other searches and those look like the olds motor mounts. My local napa had them in stock and they are only $8 a piece, so I'd say it's worth a try at least.


That's the mount that bolts to the engine itself. I am looking for the mount that bolts to the frame of the truck. I already have these mounts you show on the engine.
 

Bextreme04

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I feel like you might not need a different frame side mount.... it looks like the same frame mount is used for all V-8 engines, only the engine side mounts are different.

Just based off the selections available on the various auto parts sites. It looks like the engine bracket just goes right over the stock mounts, just like there is no difference between the BBC and SBC mounts, just the Clamshells are a little different
 

Bextreme04

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I did see someone mention needing to move the engine mounting bracket to the forward most mounting holes? Not sure what that means as I've never seen a BBO
 

OldBlueDually

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It is certainly worth a try. Right now there is no frame to engine mounts in the truck, so I do need to get them. I wonder if my 5/16" thick transmission adapter plate will effect this too.....crap, just thought of that. (Olds engine to TH400 chevy trans that is in the truck).
 

DoubleDingo

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Pics certainly helps us help you. Pics of the truck. Pics of the engine. Pics.
 

OldBlueDually

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Here are a couple pictures. Close up of engine mount on engine. Close up of passenger side frame where the frame to engine mount used to be.


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Bextreme04

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Honestly, looking at those pics, I would just get the frame mounts that are called for in the truck and try to stick it in. The engine mounts look like they would go right on to the stock motor mounts. The spacer might require you to push the trans mount back the 5/16".
 

DoubleDingo

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Honestly, looking at those pics, I would just get the frame mounts that are called for in the truck and try to stick it in. The engine mounts look like they would go right on to the stock motor mounts. The spacer might require you to push the trans mount back the 5/16".

^^^^ THIS ^^^^
 

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