I have a bit of a stupid question. I just...don't know the answer, just some generalities between the two.

What's the difference between a Small block and a Big block?

 

In a nutshell.....big blocks (generally) have more cubic inches than a small. the block, pistons, crank, rods, heads, intake etc...are larger than a small block. To put it bluntly....a big block is basically a small block on steriods.

 

Those are old Chevy terms that have entered the language. Ford uses engine "Families".

 

The biggest issue is weight and overall size. A big-block is a larger engine and may take some squeezing to fit it into a car/truck made for a small-block. The advantage to a big block is that the larger size allows larger bores and longer stroke for more displacement (cubic inches).

It is possible with certain small-blocks to get the best of both worlds. A good example is the 351 Windsor Ford small-block. It is of the same block family as the 302 (5.0) and 289 V8 small-blocks. The 351W can be stroked (extending the amount of overall travel of the piston in the cylinder) and bored (changing the width of the cylinder) to get over 425 cubic inches which puts it into the category of a medium size big-block as far as displacement goes.

For comparison the old popular Ford big-block is the 460, which can also be bored and stroked to well over 500 cubic inches. But big-blocks don't always need to have big cubic inches to be a big-block; The Ford 352 is about the same displacement as the 351W but had a much larger, heavier block since it is part of the FE family of big-blocks.

 

See, I knew all those generalities, and the boring/stroking of the engines. I just didn't know if there were any definitative criteria that denoted that an engine would be a Big Block.

I however didn't know that a 351 could achieve 425 ci's! Good god...give me that stroker crank. I still prefer to have a huge bore and a shorter stroke (revvier) but...*shrug* that's still alot of engine...

 

From what i understand, if the stroke is larger than the bore size, it is a small block, and if the stroke is smaller than the bore, it is a big block, pretty sure thats the way it goes. I just have them memorized though:
FE big block
385 series big block
Winsor series small block
Modified series Small block
240 - 300 just a tough little motor with gobs or torque

 

That does not compute.

302 b=4.00 s=3.00
351W/C/M b=4.00 s=3.50
352 b=4.00 s=3.50
390 b=4.05 s=3.78
400 b=4.00 s=4.00
428 b=4.13 s=3.98
429 b=4.36 s=3.59
460 b=4.36 s=3.85

Your memory serves you well tho.

I made a post in GC once about big/small block designations and compared some dimensions both Ford and GM and if memory serves me it came down to bore spacing.

 

Ahh..so it has to do with the distance between each individual cylinder. That would seem to make sense - as well as just the whole bigger size thing. I knew it wasn't based on just size though - cause you could have about as big a size you wanted with a smallblock. Conversly..you could have a 220 ci smallblock in a commercial vehicle that was ready to be bored more often to extend its life cycle.

Thanks guys.

Another question - on Chevy's.

What are big blocks and small blocks in their lines? is the 454 bb? 512? 612?

 

You forgot the 427! b=4.23 s=3.78

OBTW, what would you call this?
534 b=4.5 s=4.2
Extra big block perhapse?

 

can you really believe a guy who uses duct tape to fix everything on his red green show!