292 to 350 Swap

Empire402

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I have a 1984 C30 crew cab with a tired 292 I6 and I am looking to swap in a small block 350. Will I need to change the motor mount perches (brackets that connect from the frame to the cross-member). If I need to change the perches will I need ones from a C30 or will C10/C20 ones work and what about years, will 73/87 work or do I need ones from 81/87? Any help would be appreciated.
 

Bextreme04

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I have a 1984 C30 crew cab with a tired 292 I6 and I am looking to swap in a small block 350. Will I need to change the motor mount perches (brackets that connect from the frame to the cross-member). If I need to change the perches will I need ones from a C30 or will C10/C20 ones work and what about years, will 73/87 work or do I need ones from 81/87? Any help would be appreciated.
Pics? I think there are some kind of adapters on the standard perches for the 292. I think you just unbolt the adapter and bolt in standard 350 clamshells.
 

nvrenuf

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My understanding is that that the bracket position(s?) are different from a 250 or V8. I'm not sure if the crossmember itself is different.
 

Empire402

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Here are a couple of pictures of both the driver and passenger side perches.
 

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Bextreme04

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Here are a couple of pictures of both the driver and passenger side perches.
Oh, yeah you are good just like that. The 350 or 454 would have rounded cups that sit right down on those same clamshells, no need to get anything else. My only suggestion would be to replace the current ones with new ones for the motor you are going to install. They will look almost exactly like what is there currently, but the bracket on the motor side will be different.

This is what the actual 350 mounts look like. They will be 2292 part numbers. They are the same mount for both left/right. They are directional(at least the BBC ones are), and if you put them on the wrong way the bracket won't sit down far enough for the bolt hole to line up.

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This is what the brackets on the 350 will look like.
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They are the same left/right, and are the same for SBC and BBC.
 

Empire402

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Thanks for your replies. I have read conflicting info, some say the passenger side perch is different for the 292 but most of the posts I can find are talking about trucks from 67-72 I found a couple posts on the 73-80 trucks but they were swaping 250 I6 to 350's and I think the mounts for 292 are differnt than the 250. Doing the swap on my daily driver and hoping to have all the required parts on hand so I can get it done over a weekend.
 

Frankenchevy

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I think the passenger side clamshell or perch on the engine side varies. It has provisions for a strut or rod that ties the tranny to the engine, if im not mistaken. Might just be a plate that sandwiches between the clamshell and block and may not be present on manual transmission equipped trucks.
 

nvrenuf

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@Empire402 i have a friend doing a 454 to 292 swap in an 83 K30, I checked with him and the crossmember and pass side motor mount frame bracket (I’m not talking about the mount) are different.
 

Empire402

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Can anyone help me out with a couple of photos of the frame brackets from a C30 that came with a 350? I would like to compare what I have with what would have come in 350 equipped one ton. Thanks.
 

Bextreme04

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@Empire402 i have a friend doing a 454 to 292 swap in an 83 K30, I checked with him and the crossmember and pass side motor mount frame bracket (I’m not talking about the mount) are different.
Well... maybe your friend would be up to swap the brackets, since this guy is trying to go the other way. Seems like a simple swap of the 292 bracket to BBC/SBC one. I am a little confused on why they would be different frame brackets.
 

nvrenuf

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Well... maybe your friend would be up to swap the brackets, since this guy is trying to go the other way. Seems like a simple swap of the 292 bracket to BBC/SBC one. I am a little confused on why they would be different frame brackets.

It may be that just the crossmember is different to accommodate the different position, I’ve never seen the parts side by side.

It’s going to be a while before my buddy’s parts are available, the motor is still in it and he hasn’t started on the truck yet.
 

Bextreme04

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I found a couple thread with them side by side and the bracket that bolts to the frame and crossmember is different between V-6, I-6, and V-8. The OP will likely need to just go to a junkyard and find a bracket from a V-8 truck. Looks like they are all the same for 305, 350, 400, and 454
 

mcarlo86

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The passenger side mount on a 292 is farther ahead (between the distributor and the fuel pump) where the 250 mount is behind the fuel pump in the same location as the V8's.
 

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Don't toss that 292 frame mount, someone on here or elsewhere may need it for a 292 swap in their square, and they are not as common as the v8 frame mounts.
 

captianworkbench

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That someone would be me. I could use that 292 passenger side crossmember perch. PM sent.
 

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