292 to 350 Swap

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deucecoupe

Junior Member
Joined
Jun 29, 2022
Posts
17
Reaction score
9
Location
Lake Oswego OR
First Name
Richard
Truck Year
1984
Truck Model
C10
Engine Size
350
I'm a little late to this thread. I'm doing a 250 to 327 swap right now into my '84 C10.

When I pulled off the old motor mounts on the front crossmember, there were two sets of holes - one set lower and one set slightly higher but neither forward or backward. The 250 lower sat in the lower set of holes.

I just mounted the new SBC motor mounts into the upper holes and everything is fine.

The pics from Bextreme04 were exactly what I used. The lower mounts are easy to find and purchase. I dug around on FB marketplace and craigslist to find a used set of the upper clamshells that worked perfectly. Just need paint.

This isn't a hard swap to do, but I've spent more time than I thought finding all the various brackets and pulleys.

Good luck
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
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Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
You should read the replies, it's not the same with a 292.
 

greyghost

Full Access Member
Joined
Jun 15, 2022
Posts
50
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Location
kansas
First Name
vic
Truck Year
1981
Truck Model
C10
Engine Size
250
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.
curious to know if swap has occurred yet, n wat outcome was? my thots I'm swapping out my 250 I6 for LS. The only way i know to tell is use a straight edge across bellhousing mt surface n rear side of engine mts measure distance , f numbers match good to go, if not a diff location set of holes must be used. be sure to used exact set for both sides as engine angle pitch is critical, also affects tranny angle pitch n tranny mt position stress. I believe there are 3 diff sets of mounting positions already in Xmember, b sure to clean out with thread tap. 3/8 coarse i think 18 tpi, same size as existing. clamshells mt to engine n rubber mt on Xmember. good luck on first try, no fun in a second try cept more time. check all measurements b4 hand will b best outcome..
 

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  • Screenshot 2022-10-10 at 11-06-25 Engine Mount and Bracket.png
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  • Screenshot 2022-10-10 at 11-06-57 Engine Mount and Bracket.png
    Screenshot 2022-10-10 at 11-06-57 Engine Mount and Bracket.png
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