i know this has probably been answered before, but i searched and couldn't find anything. this is probably a really easy question too, but all the people i've ever talked to can't give me a very good answer. what is the difference between a big block and a small block? is there a distinct line where it switches? or is it just the "heavy dutiness" of an engine (wall thickness etc.)? i would love to find a good answer to this question.
thanks

 

I submit this to you for information.

Short Block: An engine WITHOUT the head(s). Usually includes the crankshaft, camshaft, and pistons.

Long Block: An engine WITH the head(s). Usually does not include the oil pan, valve covers, and manifolds.

Small Block: The smaller of a manufacturers two series of engines.

Big Block: The larger of a manufacturers two series of engines.

There is an overlap of small and big block displacements. Note also that a small block can be a long block. The terms define different characteristics of the engine. Doc.

 

Big Block and small block are more of a chevy and dodge thing than a ford. We do refer to the 385 series and FE series as big blocks. The 220 - 351W blocks are considered small blocks. The 335 series is highly debated. Cubic inches or wall thickness has very little to do with it. Ford makes improved 351W blocks that will take a larger bore than my 390. Ford made many different V8 blocks and chevy only made 2 different styles. If you are racing your ford in a small block only event you will probably need a windsor series engine. The cleveland might also be accepted.

 

Thank you Ratsmoker, I meant to mention that term being a "non-ford" term, Much like posi-trac.

 

We posted at the same time. I had no idea you had answered

 

thanks for the info. so there really is not a distinct big and small block, just a way that certain people refer to different blocks.
thanks

 

Heres some mud in the water, so to speak...

The small block has a bore spacing of 4.380",
The 335 series is a small block, Bore spacing 4.380",
The FE is neither a big block, or small block, same
goes for the Y-Block...
The 385 series is a big block, bore spacing of 4.90"

But, the 351M/400, has a deck height nearly 385 series
tall, (10.302" vs 10.322") but the small block bore spacing.

Are we confused yet??

 

The FE was a big block long before the 429/460 was around. Plain old fact.

 

so what's the deal with the 351W block that you said can take a bigger bore than a 390? how do you get one of those, and how much bore can they take?

 

Dart makes a block that they claim will take a 4.185" bore. It comes with a standard 4.125" bore. Not a whole lotta 390's out there that will safely run this wide but a very very few of them will.

 

I've read about that block, I was hoping you were talking about some long lost factory block. The experts at Car Craft said that the Dart block could probably go to 4.200" without any problems, but I think I'd be happy with whatever they'd recommend if I was gonna pay $2,000 for an engine block.

 

I don't know of any siamesed factory 351W blocks but I am no windsor history buff. I think ford makes some motorsport blocks that will go pretty far also.

 

How about we simplify this. If a 289 head will bolt on, it's a small block. If a 428 or 429 head will bolt on it's a big block. We can't go by bellhousing size or the chebbies would all be the same.

 

The standard 351W can be stroked to 427 cu.in., by using a highly modified 400M crank and 360 Mopar rod's. This can be bought from PAW racing.

 

FRPP Sportsmans 351 block 2 bolt main $1200. Siamesed 4 bolt main $1700-$1800. Prices may be wrong. Look up Ford Motorsports 351 block on Google and you'll find some info.