Engine swap From 250 6 cylinder To 350 sbc

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Ken B

Ken B

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Question oh wise ones.....I got the old exhaust outta the way and I have 4 main bolts loose but still in place. So I have electrical connections and motor mounts to disconnect still. If I pull the engine with the manual trans in place. once I unbolt the 4 bolts connecting the trans and engine and start to pull the engine , will the trans stay somewhat in place?
the trans mount bolts and driveshaft would be the only support.
 
Bextreme04

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Ken B said:
Question oh wise ones.....I got the old exhaust outta the way and I have 4 main bolts loose but still in place. So I have electrical connections and motor mounts to disconnect still. If I pull the engine with the manual trans in place. once I unbolt the 4 bolts connecting the trans and engine and start to pull the engine , will the trans stay somewhat in place?
the trans mount bolts and driveshaft would be the only support.
Click to expand...

No, you will want to support the front of the trans with something. Most people just run a ratchet strap under the front of the trans and over the frame rails to hold it up.
 
Ken B

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kinda what i thought but didnt want to get to the last bolt and have a surprize .
just working on electrical disconnections. got hyd clutch cyl off.

It has been so much freaking help on this forum. I woulda gone bald (er) scratching my head on some of these things or gotten hurt even.
Thanks for to all for sharing all your knowledge and experiences.
 
Ken B

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just a couple bolts away from pulling my v8. question. I am pulling with a manifold lifting plate, any preference or requirements on what grade bolts to use? my carb has 2 long and 2 short bolts so I have to get some bolts, just didnt know what grade was needed?
 
Bextreme04

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Ken B said:
just a couple bolts away from pulling my v8. question. I am pulling with a manifold lifting plate, any preference or requirements on what grade bolts to use? my carb has 2 long and 2 short bolts so I have to get some bolts, just didnt know what grade was needed?
Click to expand...

SBC doesn't weigh enough to break even one 5/16" bolt of any grade, let alone 4 of them. Get whatever is available and cheap. You should be able to use any 5/16-18 x 1" bolt and send it.
 
Ken B

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thanks to all who shared the wisdom!!. got it out. now to degrease/remove the 1/3 of an inch of grime. after degreasing remove bell housing and flywheel get it on engine stand.
It is remarkable when you dismantle 2 trucks just how much space it takes up....
 
Ken B

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question of the day......i have removed the bolts connecting the bellhousing to the engine block. but it wont budge. dont want to hit it too hard with a hammer.....am i missing something?
the passenger side flexes and moves a bit when hit, but the drivers side is still very tight.
 
Ken B

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housing is off,,,but maybe my BFH was too big. cracked the housing. those guide pins suck.
 
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Ken B said:
housing is off,,,but maybe my BFH was too big. cracked the housing. those guide pins suck.
Click to expand...
That sure sucks.

I've always had'em come loose just by wiggling the tail shaft.

You might put a little grease around those dowel pins next time.
 
Ken B

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fortunately I was pulling the bellhousing off from a manual trans. I am using the engine with a auto trans....
 
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into this swap myself, found the mount location to bellhousing is shallower in the v8 than the 6 by 1/4" - 5/16". Working with the SM465, hopefully there is room on the cross member and trans mount to shuffle up to the v8. 1984 K1500 pickup had to 250
 
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Bextreme04 said:
I would be careful doing that with you being in Indiana... the trans will have a hard time coming up to temp when the outside temperature is below zero. The 350 trucks with an auto trans didn't just have the trans cooler in the tank, they were also bigger radiators. I would try to source the right radiator and fan shroud, as well as having an external cooler. Your trans(and engine) will thank you. I have a complete original radiator and fan shroud for a 350 with auto trans, but I'm pretty far away from you.
Click to expand...
looked at this while comparing my 250 to 350 donor truck. Other than the trans cooler in the th400 model the radiator of the C20 is the same dimensions tank and core as the 250 engine had and yes both are still genuine GM parts.
 
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Jdgrant96

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Roostius_Maximus said:
into this swap myself, found the mount location to bellhousing is shallower in the v8 than the 6 by 1/4" - 5/16". Working with the SM465, hopefully there is room on the cross member and trans mount to shuffle up to the v8. 1984 K1500 pickup had to 250
Click to expand...
I swapped my 250 out for a 350 approximately 3 months ago. My truck is a 84 K10 with an SM465.

Anecdotal only but when I dropped the small block in I did not have to change a single thing transmission mount wise. All I did was loosen the frame side engine perches and it fit right in.
 
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