What is a big block, and a small block?

Question

Just out of curiosity, what does a small block and a big block meen? Other than one is small and one is big. Thank you. :)

Answer 1

exactly what it states,, small block and big block refer to the cubic inch displacment,, of an engine block,, most small blocks have 2 bolt main bearings, while big blocks have 4 bolt main bearings,,, a small block has a smaller bore and stroke per cylinder, and a big block has a larger stroke and bore,, a big block has far thicker cylinder walls and crankcase webbings as well as stronger main bearings, big blocks can produce more horsepower than small blocks, due to their strong structures

big and small blocks do not just pertain to chevy,, though chevy is most common,, ford and mopar also have big and small blocks,,,, heres some examples

chevy
small block(std),,, 302 (yes chevy had a 302 also), 305 and 350,, big block(std),,,, 396, 427, 454 and chevy makes b.blks. by Merlin which range in cid of 532 to 780 cu in,, ( strictly drag racing blocks)

ford,,,,
sm blk,, 289, 302, 351 windsor and cleveland,,,
b blks,, 351 modified, 428, 460

mopar
sm blks,, 318, 340
bg blks 383, 426 wedge and hemi,, 440

pontiac,, im not much into them but heres a link
http://forums.performanceyears.com/forums/showthread.php?t=468629&page=1&pp=20

Answer 2

The size of the engine in cubic inches. Mainly referring to V-8's...
It is for classification purposes to differentiate the larger cubic inch engines from the smaller ones. A lot have interchangeable parts between engines the same block size, but not between small and big.
e.g. A Chevy 350 is small block while a 427 is a big block.

They can be ANY manufacturer not just Chevy or ford.

Not all small blocks are 2 bolt mains. High performance and heavy duty (race or truck) can also have 4 bolt mains.

Answer 3

i would also add that i myself would call small blocks a family and big blocks a family too...because the small block parts will interchange with each other like Chevy 265 to 400 CID can use most but not all the same parts and the same for 396 to 454

calling a engine big block or small block by its CID does not work in a Chevy because a big block 396 has less cubic inch displacement than a 400 small block even if it looks bigger on the outside

Answer 4

From the way I understand it : a chevy 350 cubic inch engine is a small block V-8, and when you get to a chevy 454 cubic engine, it is then considered a Big Block. The same goes with a ford 351 (5.8 liter), and a 460 (7.5 liter). So basically a small block V-8 is in the 5 liter range, and anything bigger is supposed to be a big block.

Answer 5

the biggest diffefrence is the main bearings , a small block has 2 main caps and a big block four and usually anything over four hundred cid is a big block save for certain exceptions , like the gm 400 is really a small block, also the heads are bigger and the block is bigger on big blocks to allow for strength. big blocks also look way bigger compared to small blocks. have larger and heavier rods and pistons thats why most big blocks arent good for anything over 5-6 k rpms they are to heavy and usally run better with a shorter and more powerfull stroke rather than a small block with a longer and faster stroke.

Answer 6

Very nice answer Mr. John C. Very accurate. Nice Job!!
My dad built a 1934 Ford 3 window coupe that had a 454 Big Block that had been board out to be a 468 Big Block. In Texas talk, " That thing would run like a scalded dog."

Answer 7

They refer to the Chevy v8 engine. The small block, also called the mouse motor started at 265 cubic inches in 1955. Through various changes it eventually grew to 400 cu. in., but was still referred to as a small block.

The big block was a totally different motor, also called the rat motor. I think it first came out in 1963 as a Nascar motor. Most common sizes are 396, 427 and 454 cu. in.

Answer 8

That is exactly what it means. A small block refers to particular GM engines based on the original GM V-8 Chevy Engine from 1955. A big block has a larger casting, and bigger bore.

Answer 9

one is small the other is big. Meaning the engine casting is smaller or bigger than the other thus taking up more or less space in the engine compartment under the hood. Engine displacement and horsepower rating can approach the same number but the big block will have thicker walls within the engine casting.

Answer 10

A big block is anything 400+ cubic inch displacement. a small block is anything under 400 CID