Need help with installing a 454 in a 1979 GMC Sierra 4x4 frame

[varnell1980]

I’m currently restoring my dads 1979 GMC Sierra 4x4. It came with a 350 in it. I bought a Gen V 454 out of a 1991 Suburban and converted it to carbureted. My engine is finished and ready to be installed in my frame. I bought 454 engine mounts but they won’t fit the frame mounts. I read that people are using 350 motor mounts and they are working. They match up to the frame mount and I installed them on my clamshells and lowered my engine into my chassis. One side the holes matched right up and the other side was off about an inch. I’m at a loss on what to do. The oil pan clears my engine crossmember about 1/2 an inch so I’m afraid if I use 350 clamshells that it will hit. Do in need to find 454 frame mounts to bolt in? Please help!

 

[Strick]

So you have new frame mounts installed already & the Big Iron won't fall into place? Old mounts will break & move around inside the metal biscuit. If new ones are on then I'd check & make certain the trans mount(s) was good. If it's 4x4 then the trans will list to the right due to the t-case drop. That could also throw off you engine mount alignment.

HS

 

[varnell1980]

I bought new 350 motor mounts with the rubber inside and actually used window weld to put in all the open space inside them to make them stronger. The 454 ones I bought wouldn’t match up holes with my frame perches. The 350 rubber mounts match up so I took the 350 rubber mounts and attached them to the clamshells on the sides of the engine and lowered the engine down on the perches. One side lined up and the other side was an inch off. I wonder if I need to set it down to where it’s the same distance between all the bolt holes and drill out the holes on the perches to make it work. I’m mating the engine up to a Muncie 465 4 speed with a NP205 transfer case.

 

[varnell1980]

Also I forgot to say that I just sat the engine down in without the transmission and transfer case on it yet.

 

[varnell1980]

And I think my terminology is off a little. Lol. I’m calling the parts that bolt to the engine the clamshells and I think people are calling those the cups. I’m calling the metal parts with the rubber inside them the engine mounts and maybe those are the clamshells? And the parts that are bolted on the top and sides to the frame with the holes in them for the rubber mounts to bolt to I’m calling the perches. I won’t be offended if y’all fix my terminology. lol

 

[Craig 85]

All I can offer here is the pictures I took of my truck when the engine was out. K30 with a factory 454. Hope this helps.

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[9999]

Have you figured out what headers you want to run also?

I’ve got a 454 that was swapped out for a 305, but was already done with mounts and headers.

 

[Bextreme04]

And I think my terminology is off a little. Lol. I’m calling the parts that bolt to the engine the clamshells and I think people are calling those the cups. I’m calling the metal parts with the rubber inside them the engine mounts and maybe those are the clamshells? And the parts that are bolted on the top and sides to the frame with the holes in them for the rubber mounts to bolt to I’m calling the perches. I won’t be offended if y’all fix my terminology. lol

The 454 mounts use different holes than the 350 ones. I've seen a thread somewhere on here that shows the different holes and stuff from a factory manual. You can probably find it in one of the chassis manuals in the resource library.

Its also important to note that the clamshells(the part that mounts to the frame with the rubber inside) are directional. They have an up and down side, and if you put them on the wrong way then the hole will not line up when the cup sits down on them.

 

[Dooley]

Likely you will need this fuel pump for clearance on the BB.

Carter M4530 Carter Muscle Car Mechanical Fuel Pumps | Summit Racing

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[varnell1980]

Thanks everyone for your responses. I finally got the motor in. Ended up buying competition style motor mounts from Off Road Design. They fit and had enough clearance for my long tube headers. I have a new summit racing 8 inch oil pan on it and it barely clears on the right side. Here are some pictures of it in.