Big Block or?????????????
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Senior User
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From: Michigan
Big Block or?????????????
I have a dumb question. But im going to ask anyways. I have a 79 F250 4x4 400 and c6 auto. Trans went and i found a 78 f150 4x4 about 3 hours away from me. The f150 has a 351 with a c6. My question is how do I know if it is the big block like my 400? The guy thinks its a 351m which is the same. but he is not sure. How can I tell from pictures of the motor? it is all good runs and drives good but the frame broike and the guy only wants 300 for motor trans and transfer case. But its useless if its the small block. And 350/gallon i dont want to waste a trip. I should know but im having a brain fart I guess. Thanks Guys.
More Turbo
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What would the 400 be stroked from? same series as the 351C which came out a year earlier, but the blocks are different with the 400 being a little taller. just asking, always willing and ready to learn something new
Posting Guru
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Big block/small block is more a GM thing and is a slang term. It typically refers to the larger size engine family within each manufacturer. There are no real guidelines, not CID, nor HP or weight etc. Hence, the FE/FT is usually considered a "big block" even though CIDs were from 330-428 and the 385 series has an even larger displacement . The 400 came before the 351m so I would guess a 351m would be considered a "destroked 400" if anything.
More Turbo
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Cargo Master
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From: Lost In a Pit of Despair
Generally people consider the 335 series (351/400) small blocks, while the 385 series (370/429/460) is considered big block
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Posting Guru
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From: Mississippi
. A 351m/400 dwarfs them. Or the FE? Big block/small block is nothing but a slang term and doesnt mean much if anything.
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Fleet Mechanic
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And to further muddle to terminology.....I've had guys argue with me about the "M" in 351M telling me it stands for Midland or Medium. Whatever!!!!! Then there was this cat who was a self proclaimed genius because he worked on dragsters and knew all about 351M's and 400's.....I just walked away. Don't even want to entertain dudes like that.
To further help I.D the engine....351M-400's have the thermostat housing cast into the block.
To further help I.D the engine....351M-400's have the thermostat housing cast into the block.
Postmaster
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From: Taxachusetts
I have a dumb question. But im going to ask anyways. I have a 79 F250 4x4 400 and c6 auto. Trans went and i found a 78 f150 4x4 about 3 hours away from me. The f150 has a 351 with a c6. My question is how do I know if it is the big block like my 400? The guy thinks its a 351m which is the same. but he is not sure. How can I tell from pictures of the motor? it is all good runs and drives good but the frame broike and the guy only wants 300 for motor trans and transfer case. But its useless if its the small block. And 350/gallon i dont want to waste a trip. I should know but im having a brain fart I guess. Thanks Guys.
8 valve cover bolts, 1" rib on the block by the distributor right side (looking from the front), exhaust bolts at ~ 10 and 4 o'clock, water neck on the block, dry intake manifold.....all mentioned above.
Buy it/them...good price, and you'll have a spare motor!
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