I have a very hard time putting my thoughts into words, can some one help me explain to my ag. teacher what the difference is between a big block and a small block motor. Thanks guys!

uhhh... different block. there isn't really any defining "motor size" that makes a motor specifically a big or small block. you can have a small block with more displacement than a big block, and it's still called a small block.

What Redass said plus. Most of the auto makers would use two (somtimes more) seperate block castings. For example, GM's small block 327 and 350 look the same from the outside but the bore and stroke are different, they also share external accessories and most times heads and intakes. At some point the block is only going to accomidate a certain amount of cubes, so a new larger casting was needed, hence the big block.

tell him ones big and one a wee lil ole thang...duh :D

Yea I've always wondered. So like how exactly do you tell the difference in a big block vs. small block. I mean there has to be some defining line that says this side is small this side is big. It can't just be guess work. "Well this en here looks smaller than this en here .. so this en must be a big block.. duhhh yea thats right, this right heres a big block boys, we gonna put it in our uhh tractor over there by them hay bales."

I'm lost.

the actual size of the block is different. 302,331,347,351....small block. 428,460,etc...big block, if you seen 2 side by side youd know.

Ford and Chevy called their V-8's small or big blocks. The 302/305 and lesser c.i. motors are small blocks. Most stock c.i. motors over 400 are big blocks. The grey area is in the 300's. Ford built 3 different 351 c.i. blocks. The small block 351W (windsor) is based on the 289,302 style and has a smaller exterior dimension. The big block 351C (Cleveland) has larger outside dimensions, but still has bore and stroke equalling 351 c.i. Most parts don't interchange. The 351M (modified) is sister to the 400M and even less parts interchange, especially the head gaskets come to mind.

big block and small block have nothing to do with displacment chevy made a big block and a small block 350 basicaly it was physicaly size of the block the big block is bigger than the small block.

btw if you have to do a report stick to chevy's fords and dodges can get confusing at first.

ORIGINAL: ikeybmg

tell him ones big and one a wee lil ole thang...duh :D


HEY Nice looking car u got there buddy!

Check out the size/weight difference of crankshafts small block vs big block


http://mustangandfords.com/techarticles/127_0409_wind_sb3_a_z.jpg

That's a 427 Windsor stroker crank on the left, and a 428 FE crank on the right

The 428 has a 4.13 inch bore, the 427 windsor has a 4.04 inch bore.


However, the same block (the FE block) was also used for as small as a 352 ci engine, and has the same bore as a 351 (4.00 inches)

But the same FE block (well, certain productions of it) were bored out to a 4.23 inch bore, and these were called the 427 FE's

the biggest diff. i see there is length.

ORIGINAL: JD1969

What Redass said plus. Most of the auto makers would use two (somtimes more) seperate block castings. For example, GM's small block 327 and 350 look the same from the outside but the bore and stroke are different, they also share external accessories and most times heads and intakes. At some point the block is only going to accomidate a certain amount of cubes, so a new larger casting was needed, hence the big block.

This is the best simple definition there is.