engine question

[tomls1]

stupid engine question

for years i've always heard people talking about "big blocks" and "small blocks". particularly the chevy "350 small block". my question is, why the small/big designation? is there actually such thing as a "350 big block"? what makes an engine a big/small block?

any clarification would be greatly appreciated.

 

[Ken]

"Big" and "small" refer to the cubic inch displacement of the engine block. Nowadays it is possible to build a 454 ci small block, but it still doesn't live up to the torque rep the big blocks have. There's an old saying: "There's no substitute for cubic inches"

Small blocks run the gamut from the lowly 262ci (if they even still make it - and I don't mean the 265ci original small block, I meant 262) all the way to a 400 cubic inch version, from the factory. Big blocks have displacements ranging from the old 396ci engine up to the new 502 and 572 cubic inch versions. Hope this helps your understanding some.

 

[bossvette]

when you think about it it is not a stupid question because Chev, Ford and Mopar all have big and small blocks. and the big block Chevy came in sizes from 366 to 502 from the factory and the small block came in sizes 262-400. from the Chevy side of it the "small block" has been produced since 1955 and has been pretty much the same until the new LS1 came out. the big block has been around since 1965 at 396 to the 502 crate motors of today 01

at what point do you call them "big Blocks"?


ps some of the early chrysler hemis were actually small cid wise but sure filled an engine bay

 

[Ken]

I knew I'd find something if I looked hard enough! :gap

572 CUBIC INCH BIG BLOCK

Marketing name has yet to be decided, this is based on the tall deck bow tie block in two compression ratios, 9.6 and 12 to one. This will be a regular production crate engine.

That was taken from the Superior Chevrolet Performance Parts Center site.

_ken

 

[tomls1]

ken -- would the 454ci that your refer to be accomplished by taking a small block engine (ex. 350) boring the cylinders and using large volume heads?

so. since the 350 falls into the small block catagory, am i to understand that there is no such thing as a 350 big block? i have a friend who often refers to a 350 big block...is this inaccurate?

thanks for the responses...this is great info.

 

[69_Dream]

Interesting post... hmm...

How does one make the distinction between the 2 if a 396 is a big block and a 400 is a small block?

Sly

 

[vette-dude]

Weight. The Big block has more meat around the cylinders and water jackets thus it weigh more. Or--one makes a better anchor than the other.

Randy

 

[bossvette]

just speaking gen 1 chevy engines this is a small block the easiest way to tell it from a big block is the center two cylinders have the exhaust next to each other. I know there are some good big block pictures out there so send'um in

 

[Tom73]

Big block, small block, hummmm. The big block has a larger block (not displacement) than a small block. The overall block is larger and heaiver. Just look at the valve covers. The "big block's" valve cover is almost twice as wide as the "small block's".

tom...

 

[Tuna]

The big block has a larger block (not displacement) than a small block. The overall block is larger and heaiver.

The bore centers are farther apart on the "big block" than the "small block" and the deck height is usually higher. This is the starting point for the difference in size. It allows for more growth than the small block.

While it is possible to find 427+ cubes in a "small block" you will not get much more than that out of the available space. The "big block" can be bored and stroked to another 150+ cubes.

You can find many small blocks with 400+ cubes and you can find big blocks with <400 cubes. Just depends you what you want and how you want it.

 

[Ken]

ken -- would the 454ci that your refer to be accomplished by taking a small block engine (ex. 350) boring the cylinders and using large volume heads?

The 454 small block from World Castings can now be built due to the release of Fel-Pro's new 4.250" gasket (PN 1036). Previously they were limited by the readily available performance gaskets dimensions of 4.185" maximum.

You start with a 400 block, as I did, and go from there. Mine is built to 417ci.

_ken