Big block guys, help me out here

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Wumbo

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I'm pulling my 454 and replacing it with a freshly built 468. Trans is a SM465. Truck is a 86 C20.

Last time I pulled this engine I couldn't get the engine high enough to clear the mounts without the trans hitting the transmission tunnel. I couldn't separate the engine from the tranny. Had to bolt the trans back to the engine and pull them as a pair. The service manual says that you can pull the engine sans trans, but it doesn't mention the sm465, seems the TH400 would be smaller and it would be a non issue.

My truck does not have the removable hump either.

Any of you guys pulled this feat off? I'm giving it another go tomorrow. If anyone has a suggestion, I'm all ears.
 

Matt69olds

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If the problem is getting the engine high enough, and the hoist won’t go any higher, let the air out of the tires to drop the front of the truck.
 

Jethro224

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How about just remove the mounts?
 

Paladin

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Seems strange not being able to unbolt the tranny from engine, you must not have busted and scraped enough knuckles yet!:cheers:
 

Vbb199

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Seems strange not being able to unbolt the tranny from engine, you must not have busted and scraped enough knuckles yet!:cheers:


My thoughts exactly, someone hasn't punched the flexplate/flywheel enough trying to pry the two apart lol
 

Wumbo

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I didn't have any problem unbolting the trans, and I have plenty of height as far as hoist goes.

The engine half of the motor mounts wont go higher than the frame half of the mount because the trans hits the tunnel, so I can't slide the engine forward off the input shaft. If the trans tunnel was an inch taller I would have all the clearance I need.

I think I'm going to have to unbolt the motor mount brackets from the frame.
 

Big Chip

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I didn't have any problem unbolting the trans, and I have plenty of height as far as hoist goes.

The engine half of the motor mounts wont go higher than the frame half of the mount because the trans hits the tunnel, so I can't slide the engine forward off the input shaft. If the trans tunnel was an inch taller I would have all the clearance I need.

I think I'm going to have to unbolt the motor mount brackets from the frame.
Are you able to unbolt the trans cross member and take the trans out the bottom or tilt it enough to to get off the engine mounts?
 

nvrenuf

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I’ve had big blocks in square bodies since ‘87 and I’ve never pull a motor with the trans.

I usually pull the front tires to lower the truck and then get it the chain as low as possible. I’ve used different hoists and always been able to get them out.
 

Wumbo

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Last time I did this I rigged the engine with a couple chains and a chain fall.

This time I'm using an engine leveler.

It's coming out one way or another though.
 

Customblue

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You can pull them out together but it is easiest to remove the front clip so you only have to raise it a foot or so
 

shiftpro

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Time for a 1" body lift?

This illustrates the variations off the factory floor. One of the pieces of lift vs tire clearance puzzle is where the cab is sitting on the frame in relation to the front axle. Often a cab can be slid back on the mounts nearly one inch. Sometimes a cab can be slid forward, meaning it is already as far back as it can be. Sounds like your cab is sitting forward a bit. Also perhaps the thickness of the cab mounts (bushings). Have you changed yours? Rubber or poly?
 

Wumbo

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Time for a 1" body lift?

This illustrates the variations off the factory floor. One of the pieces of lift vs tire clearance puzzle is where the cab is sitting on the frame in relation to the front axle. Often a cab can be slid back on the mounts nearly one inch. Sometimes a cab can be slid forward, meaning it is already as far back as it can be. Sounds like your cab is sitting forward a bit. Also perhaps the thickness of the cab mounts (bushings). Have you changed yours? Rubber or poly?


Factory cab mounts. Cabs never been off. Never felt the need to change them, since they look fine.

You must be registered for see images attach
 

Wumbo

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Time for a 1" body lift?

This illustrates the variations off the factory floor. One of the pieces of lift vs tire clearance puzzle is where the cab is sitting on the frame in relation to the front axle. Often a cab can be slid back on the mounts nearly one inch. Sometimes a cab can be slid forward, meaning it is already as far back as it can be. Sounds like your cab is sitting forward a bit. Also perhaps the thickness of the cab mounts (bushings). Have you changed yours? Rubber or poly?

I think you nailed it. But, the assembly line guys put it where it is.
 

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