at what ci does a block become "big"

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RangerJoe

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You lost me.... Are you asking what cubic inches came in a big block?

Joe
 

gearheadboy

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always wondered
With all due respect.....LMAO! Now that I have that off my chest, some car manufacturers produced engines of different configurations. Some were smaller blocks than others. Cubic inch really had nothing to do with it. For instance a 351w may be considered a small block, whereas a 351c or 351m may be considered big blocks or mid blocks. Generally speaking engines configured from most manufacturers having large cubic inches are big blocks because its hard to fit 460 cubic inches in a reliable small package. I'm sure you'll get different stories here but this is a general explanation.
 

HuskerNation

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So a 396, 366, 350, etc are not big blocks I guess.
A 350 is a small block. SBC. Thats why you will hear terms that some mustangs have a SBC 383 stroker.

It all depends on manufacturer and this question is one that has way too many different views for one to be absolutely correct. This is what Chevy considers on how theirs are rated. They don't base a SBC or BBC off of CI, but they base it off of displacement.

Small Block: The smaller of a manufacturers two series of engines. In the case of Chevy, the small block includes the 262, 265, 267, 283, 302, 305, 307, 327, 350, and 400.

Big Block: The larger of a manufacturers two series of engines. In the case of Chevy, the 366, 396, 402, 427, and 454.
 

gearheadboy

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A 350 is a small block. SBC. Thats why you will hear terms that some mustangs have a SBC 383 stroker.
Like I stated originally, there will be many opinions. Having worked at a dealer that sold Pontiacs which could be equipped with either a 350 Pontiac (which the literature termed the BIG block at that time) or a 350 Chevrolet which was referred to as a small block, I'll have to beg to differ with you.
 
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MikeySmikey

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Generally it has to do with bore and stroke. Most small blocks (with some exceptions) have a 4 in. bore and 3.5 in. stroke. Most big blocks have a 4.25 in. bore and 4 in. stroke. Granted this isn't always the case but it's what I've found most of the time. As I said, there are exceptions. The Chevy small block 400 has a 4.125 in. bore and 3.75 in. stroke. The biggest difference is the length of the rods. Most small blocks use a 5.7 in. rod, where as big blocks use a 6.13 in. rod. Using simple logic, what makes an engine a small or big block is the length of the cylinder itself and the stroke of the rod & piston.
 

gearheadboy

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Generally it has to do with bore and stroke. Most small blocks (with some exceptions) have a 4 in. bore and 3.5 in. stroke. Most big blocks have a 4.25 in. bore and 4 in. stroke. Granted this isn't always the case but it's what I've found most of the time. As I said, there are exceptions. The Chevy small block 400 has a 4.125 in. bore and 3.75 in. stroke. The biggest difference is the length of the rods. Most small blocks use a 5.7 in. rod, where as big blocks use a 6.13 in. rod. Using simple logic, what makes an engine a small or big block is the length of the cylinder itself and the stroke of the rod & piston.
Once again, that has 0 to do with big block or small block. And if every small block had a 3.5" stroke and a 4" bore, they would all be 350's. Well, depending on the rod.
 

srtthis

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A 350 is a small block. SBC. Thats why you will hear terms that some mustangs have a SBC 383 stroker.

It all depends on manufacturer and this question is one that has way too many different views for one to be absolutely correct. This is what Chevy considers on how theirs are rated. They don't base a SBC or BBC off of CI, but they base it off of displacement.

Small Block: The smaller of a manufacturers two series of engines. In the case of Chevy, the small block includes the 262, 265, 267, 283, 302, 305, 307, 327, 350, and 400.

Big Block: The larger of a manufacturers two series of engines. In the case of Chevy, the 366, 396, 402, 427, and 454.
They made a 350 big block also
 

srtthis

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The way they word big block vs small block in the 275 rules is...

Big block Chevy short deck is 9.8" deck height
Big block Chevy tall deck is 10.2"
Big block ford is 10.3" deck height
Big block mopar is a 10.6" deck height.

Small blocks are anything less then that with a stock bore space for GM ford or mopar.
 

gearheadboy

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A 350 is a small block. SBC. Thats why you will hear terms that some mustangs have a SBC 383 stroker.

It all depends on manufacturer and this question is one that has way too many different views for one to be absolutely correct. This is what Chevy considers on how theirs are rated. They don't base a SBC or BBC off of CI, but they base it off of displacement.

Small Block: The smaller of a manufacturers two series of engines. In the case of Chevy, the small block includes the 262, 265, 267, 283, 302, 305, 307, 327, 350, and 400.

Big Block: The larger of a manufacturers two series of engines. In the case of Chevy, the 366, 396, 402, 427, and 454.
"They don't base a SBC or BBC off of CI, but they base it off of displacement." WHAT? REALLY? cid= Cubic inch displacement. Its the same thing.
 

MikeySmikey

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Once again, that has 0 to do with big block or small block. And if every small block had a 3.5" stroke and a 4" bore, they would all be 350's. Well, depending on the rod.
So basically you're saying that the info I gave is entirely incorrect. Did you miss the part where I said there are exceptions, because I'm pretty sure I did, and also said that it was most not every.
 

gearheadboy

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So basically you're saying that the info I gave is entirely incorrect. Did you miss the part where I said there are exceptions, because I'm pretty sure I did, and also said that it was most not every.
Its not that its entirely wrong. The point is you can't specify that a certain stroke or bore has anything to do with being designated a big or small block. You also stated that MOST but not all small blocks have a 3.5" stroke with a 4" bore. That is totally incorrect. If most DID then they would be 350's, well depending on the rod variable. The stroke and bore can be anything that will work within the limits of the casting. Thus you can have a .030 over 302, .040 over 302 etc. and any small block can be stroked or de-stroked. Any of these variables will never make it a big block. Also a big block could use different rods and crank, offset grind etc to become a 200 cid engine but would still be a big block.
 

MikeySmikey

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Its not that its entirely wrong. The point is you can't specify that a certain stroke or bore has anything to do with being designated a big or small block. You also stated that MOST but not all small blocks have a 3.5" stroke with a 4" bore. That is totally incorrect. If most DID then they would be 350's, well depending on the rod variable. The stroke and bore can be anything that will work within the limits of the casting. Thus you can have a .030 over 302, .040 over 302 etc. and any small block can be stroked or de-stroked. Any of these variables will never make it a big block. Also a big block could use different rods and crank, offset grind etc to become a 200 cid engine but would still be a big block.
You raise plenty of valid points, all of which are correct. And in that sense so did I. I simply wanted to lay the basis for the differences.
 

88LX5.Oh

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As Gearhead has already stated, cubic inches has absolutely nothing to do with "big" or "small" blocks. Look at the FE 352. It is considered by most a big block yet is only 1 cubic inch larger than a 351 Windsor.

Well ACTUALLY if you want to get technical, the 351W has the SAME cubic inches as the FE 352 since both share 4" bore and 3.5" stroke. Both the 352 and 351 are truly 351 cubic inches but Ford rounded up with the FE block because most companies did that, like a GM 350 isn't a true 350, it's 349. But Ford wanted to differentiate the Windsor apart from the FE block so it wouldn't confuse people. Why think Ford called the 302 a 5.0 when in all reality it's a 4.9? Because they didn't want people to think they had a straight six in their GT Mustangs.


But to be back on topic, I don't really use block size or BS like that to classify their engines. I use "Series" to identify their engines. Windsor series, FE series, 335 series, and 385 series. If I were to see a 390, I would call it an FE but most call them big blocks. To each their own.
 
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