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I hear folks talk about wanting to install them in their trucks, just curious
to hear them define big blocks..

big block or small block

Big block has different trans bolt spacing? It can't be cubes because there's a 348 big block. Hell I'm stumped but what else is new...

Aren't the sbc from 265-400 the same block? I know the 400 is external balance. But the block is the same just different bore and stroke. The 400sbc and 402bbc have the same stroke though.. 4.125 I believe. Then 454 and 498 aka 502 is the same block. Nothing looks cooler than bbc heads though.

Well on old school Chevys, beginning with the Gen 2, 90 deg engines, if the center exhaust ports have a big space in between , it's a big block. It's a "bigger" block.( To confuse the issue the Gen 1 "W" big blocks, 348, 409 and 427.1, had the center two ports close together.) Cu in is NOT the determining factor. The pistons are spaced out for usually larger bores. The valve covers are much bigger. If the two center exhaust ports are close together, it's a small block, Of course, there are other differences. But you can see the intent by looking at the exhaust manifold up until the LS motors. The distinction is getting more and more blurred. The LS9 (known as a small block) has 638 HP out of the box and has "spread" exhaust/spread bores. Corvette is the platform for these big small blocks. Aluminum engines. When you design big bores and need strength, you have larger bore spacing. When you do that and you have super high horse power, the word "small block" has lost it's meaning almost. Big block boils down to a larger block, sort of. BBC started out being shorter but wider, that is no longer the case either. Totally Nodular dude!
BTW: most Chevy big blocks and small blocks have the SAME tranny bolt pattern. There is a BOP bolt pattern also.

I noticed that. My dad runs a caddy/ Buick/ gmc dealer. The cts-v has spread ports and its a 388cid small block I think? It's all confusing as hell. All I know is there's no replacement for displacement if you're looking for power. Ls series engines are sweet. I've had my 383 for 12 years though and can't bring myself to replace it. If it breaks I will, and I try all the time to break it. When it does happen I'm going big big big block! Like 632 cubes. My uncle has a mountain motor from his 55 belair that got wrecked. 1300 hp. Ahhhh I'm drooling

Hy guys, here is the way I understand it, the Chevy "big block" or "W" engine development began in the mid fifties. The first "big block" was the 348 in 1958, this engine was unique in that the deck or head mounting surface was not perpendicular to the bore, and the cylinder head was completely flat, that meant that the combustion chamber was above the piston but in the cylinder block. A larger engine of the same design appeared in the early sixties, a 409, this engine series eventually became as large as a 427, these engines were physically larger than the 283s and 327s of the day. In 1965 another design of "W" engine was released, this was the 396, this engine was a more conventional design in that the top of the block was perpendicular to the bore and the combustion chamber was in the cylinder head. The cylinder head was a unique design with the valve guides at two different angles in the head, this design is sometimes reffered to as "porcupine" or "canted" valve heads. The smallest of this design of "W" engine is the 366, a truck only engine there were also truck only 427 cubic inch engines which had a taller block they used taller four ring pistons. The big block displacements I can think of are, first series 348 and 409, the 1965 and up I believe designated the mark 4 engine 366, 396, 427, 454, 502, and a larger one yet that I can't remember, hope that helps to answer the "big block" question.

Uhh..... What he said....

How about GMC "big block" V6 at 305 ci? (And larger)

To keep it simple smallblocks are the 1955 Chevy V8s and variations (like LTs) up to the LS architecture introduced in the new C5 Corvette around 1998 or so.

Bigblocks are the 396 and larger (454 being very common) spread exhaust port architecture. The 348 and 409 early large displacement blocks are better described as "W" motors due to shape of valve covers.

Used generically you are just talking Chevy motors-you have to qualify if you are talking about something else, say a f@rd smallblock.
Using these definitions an LS is an LS-whether a 4.8 or 7.0 liter in size, same block dimensionally.

It's mostly internals correct? Blocks for all sbc are the same dimensionally i think. Only the w style from the 50's is completely different due to spread. 427-502 use same block?

I've seen 427 small blocks though. Is that just stroked and punched out to the gills or what? I don't think you can do it with a factory block. Maybe a world industries block or something perhaps a Merlin block?

Mouse or Rat?
Elephant or Whale?
Cammer?

a chevy 396 is a big block but a 400 chevy is a small block..
I lost a bet on that one before,

yrs ago when my son was dirt tracking we went to a local
guy for him to build up a 350, took forever but when we had it loaded it the old International my son said wait, the guy is going to get this one back, he was looking at the bill sheet
and realized he had used a 305, guy told him this was just as good, something to do with the internal stuff, I dont recall
what my son realized on the sheet but we unloaded the engine
for him to use a 350.. we picked it up a few weeks later,
I told my son that he would not know the difference by looking, he said that he would..the engine only lasted a few races..lol

We are all talking stock cu in/torque. Not bored and stroked engines or aftermarket engines. Not talking cu in to define SBC/BBC, as I said earlier. There are many modified engines.

You could have won it on a technicality. in '70-'72, there were actually two engines sold as a "400". The "Turbo fire 400" was a small block, and generally found in passenger cars, mostly Impala Wagons with the tow package. In trucks, one could get the "Turbo Jet 400", which was actually a 402 big block. I believe that one could also be optioned in Passenger cars as a "400" but is more common in trucks. The 402 was used in the Camaro, Chevelle, and Nova, but marketed as a "396".
Now, to answer the basic questions, all small blocks share the same external dimensions, most the physical differences are internal. The displacements are as follows; 262, 265, 267, 283, 302, 305, 307, 327, 350, 377 (race use only, mostly in Grand Sport Corvette), and the 400. These are factory blocks, not counting any aftermarket blocks like World Products.
Wit big blocks, there are several variations, the Mark 1, Mark 2, Mark 3 (not produced), Mark 4 (most common), Gen 5, and Gen 6. There was also a variation that was for all intents, a big block version of the LS engine. The big block sizes are as follows; Mark 1 348, 409, 427. Mark 2 427, aka, the "Mystery Motor"-race use only. Mark 3, unknown, none released to the public. Mark 4 Short Deck 396, 427, 454. Mark 4 Tall deck 366, 427. Mark 4 Aluminum block. 427 (ZL1 with iron liners), 430, 465, 495, 510 (the last 4 listed are 390 alloy, no liners, race only). Mark 5 454. Mark 6 427, 454, 502 (tall deck) 572 (tall deck).
Again, I only listed blocks manufactured by GM. All V Chevrolet engines, including the 229 and 262 V6 and the 194, 230, 250, and 292 inline engines use the same bell housing bolt pattern.
When you get into the other GM brands, that opens a whole different can of worms, especially Pontiac, which had no actual "big block" engine.

Any body know someone with a 572? My buddy Johnny just stuffed one in a 67 vette. He had top flight corvette do it. It doesn't run yet but I'm just curious if it worth $17,000? I built my blown small block for 10k and its lasted 12 years.

hollow65, figure your 10k in today's market...lol that would be over 13k now so it could be depending on what type of goodies he has in it

The idea of a monster motor sounds good but wait until you try and drive it, you will find out how good the rest of your driveline is. Having a big inch motor is worthless if you can't get it to the ground.

I can't get my small block to the ground. It's still fun. I'm afraid if I hook up I'll break it.

if we include non factory blocks, cubes doesnt matter as there is a 600 ci small block being produced.

I still like this one!!

A big block is a big block. The blocks, heads, etc. are larger. It's not a displacement thing, it's the motor design and geometry. A small block is a small block for the same reason. The LS motors are small blocks, just the newest generation of small block.