I'm Batman

I don't think they moved any engine production to Mexico until later than that, but I could be wrong.

69 Chevy

I will. It and its predecessor the 348 were the 'W' series engines from the configuration of the valve covers. Many found their way into medium sized trucks. Not a 'small block' in any respect. They evolved into the Mark II big block with their "porcupine" valve arrangement.

Billysvette

Its as simple as this,no need to debate about it.

billla

Yep, let's ignore the GEN II (LTx) and GEN III/IV (LSx) engines completely...

Boy, this has been a weird thread for such a simple question

Little Mouse

I guess the best way to say it every SBC that has ever been put between the frame rails from the factory production line has been a 4.44 bore center. Every form of BBC including the W engines uses a 4.84 bore center.

You get two flavors of aftermarket SBC with 4.44 or 4.50 bore center.

BBC aftermarket are 4.84, 4.90, 5.00 are common sizes. I did see a 5.30 bore center.

632cu. are built off 4.84 bore center the others can go well north of 800 cu.

NHRA Pro stock rules 500 engines use a 4.90 bore center limit. 4.730 bore 3.50 stroke real short deck for that 3.50 stroke.

Billysvette

Yep,cant exclude the newer engines,but i think he was talking older engines,400 sbc.

billla

The question was:

So, what constitutes a small block engine?

...and there are (currently) 4 generations

I agree that at least at the moment, the common bore spacing will do it. But maybe the only answer is that a small block is whatever GM calls a small block

ElCameeeno

With 400's wasn't there a "TurboJet" and a "TurboFire". If I recall correctly the TurboJet was the 402 marketed as a 400 in intermediate (Non SS Chevelle) and Large Cars (Impala) etc.

TurboFire was the small block siamesed 400.

...of course I may have those names reversed.

I'm Batman

I still have to vote that general engine size is what determines a "small block" vs. "big block." BBC blocks are...well...bigger.

SH-60B

[QUOTE=toddalin;1580927827]The simple answer (and certainly for Chevy) is that it is based on the bore spacing.



This is the only right answer I saw.

billla

So an LSx 454 is a "big block", just like a GEN V 454 BBC?

There are two families, and multiple generations within them - just that simple.

anips

No, I'am thinkin it would be a smaller big block than a big big block

Little Mouse

Its the very big difference in bore spacing. You can stroke a gen 1 or an LS or LXS out to the size cu. of the old BBC but its still just a pumped up in displacement small engine. The BBC is the real thing a big engine.

Your stuck with the small bore centers on a SBC.

Gale Banks 80'

My 2 cents worth. Despite GM's marketing dept decideing that it would be good for there image to call the LS Engine a SBC I don't consider it one, and never have. Its not that I don't like it, I own one its got 94k trouble free miles on it. But some times its better to let something die. One thing I have never read or herd about was why GM decided when to replace the SBC. I mean they couldn't be the last company producing a non metric engine. A more modern engine must use a more modern manufacturing process and therefore cost less, the cylinder head on the SBC had run its coarse on performance and emissions. And many more reasons. But why 1997 ? Did they feel they had to launch it with a new model Corvette? After all the Corvette has always been the test bench for new Idea's for GM but was that it? Dose anybody know when the SBC was last sold in a Vehicle? I think there were some 2000 trucks sold with them. So if the SBC was from 1955 to 2000, then the BBC has had a longer run than the SBC, 1965 to present and still counting as far as I know. Who ever said engines needed to be metric anyway.

scottyp99

The answer to this question is deceptively simple: In general, (not just talking about Chevy engines here) a small block engine has a small engine block, and a big block engine has a large engine block. That's all there is to it, really. If you want more clarification, go down to your local pizza joint and ask them what the difference is between a small pizza and a large pizza.


Keep the shiny side up!
Scott

Little Mouse

The ls engine showed up in pickups with an iron block several yrs before it showed up in any cars.

The LS has the same 4.40 bore center as the SBC it replaced the deck did go from 9.025 to 9.20. But both these figures are tiney compaired to the factory BBC 4.84 bore center, 9.80 deck height.

It for sure is SBC based.

The most disapointing thing to me was when i first read about the new SBC was they kept the 4.40 bore center.

All the nice changes and they kept the same stupid 265 chevy bore center.

mrvette

With all the information above, I never spotted the switch in the mid 80's to the roller cam and single piece rear main seal on the SBC, by '88 I think it was across the line, for instance I have a '89 factory 4 bolt main cap 355/.030 over roller engine in my car, since '97 now....various heads...iron, aftermarket aluminum, and now L98 stock aluminum, L98 cam now, after getting burnt for YEARS with a defective roller cam from TPIS, never buy a ZZ9 cam from them or anything else for that matter....long story...the ROLLER cam was junk from the git go, and I never suspected....

TERRY CLARK

Also 396BB in 1965 only!

Mike Ward

I did just that and they said the answer was $4.00

I'm Batman

I didn't say "displacement," I said "size." Physical size. Every US manufacturer has small and big block engines. Small blocks are smaller than big blocks. End of story.