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Discussion Starter #1
This may sound stupid, but what's the difference between a big block and a small block? How can there be a big block 350, but also a small block 350? I don't get it...
 

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The size of the engine block and its bore usually is the difference.
The main thing can be summed up in one word- TORQUE
 

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first of all theres no big block 350.. the smallest big block was a 366 which is a fairly rare (not the good kind of rare) truck big block (called Tall Deck)

anyways small blocks can be had in these displacements:

262
265
267
283
302
305
307
327
350
372*
383*
400

as far as I know all of them are factory displacements except for the ones i put a * next to.. those use different combinations of cranks and blocks to get custom displacement motors..

as for big blocks theres not so many... big blocks can be had in these displacements:

366
396
402
427
454
502

all of those are factory motors except the 502 which is built by chevy but never was installed in a vehicle.. only sold in crate motor form.

thats it in a nutshell like i said.. its very confusing at first, beleive me i remember trying to figure out the difference between a big & small block but you will catch on if you keep reading on team chevelle and read mags, look at pictures, etc.. btw there are even less popular sizes that i didnt mention like very high dollar 509+ big blocks and 420+ small blocks but thats a whole nother post (one which will be written by someone else!) hope this helped if you have any more questions, we will be glad to answer what we can

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Mike Reeh
Gold #34
San Diego, CA
 

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One more, a tall block 350 that was put into big trucks like a C-40 and up. Pretty much worthless for a performance engine.
 

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add this as well , the smallest cid bb and the first of them all was the 348 introduced in '58 , which was then followed by the infamous 409 .

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The 348 and 409 big blocks were a totally different design from all the newer ones, so they kinda don't count in this discussion. Pontiac, Buick, Olds, and Cadillac motors are different from Chevy motors, although some of the designs are based to some extent on the Chevy motors.
 

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Discussion Starter #8
Thanks guys, you've always been there for me, even in my most ignorant states of mind...
 

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All Pontiac blocks are the same size. There is no "big block" or "small block" Poncho. The big displacement Pontiacs, 455, 421, 428, do have a larger main bearing size-but the 400 has the smaller journals.

The only GM "big block" 400 engines are the two versions of the 400 Olds. (same basic block, but different bore/stroke ratios) Chevy sold some cars with "400" on the fenders, and a big block under the hood, however those engines were really 402's.

There is also the ultra-rare 427 version of the 348/409 "W" block. It was a limited production, one year ('63?) wonder. It is not the same as the later 427.
 

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Schurkey,
Kinda yes, kinda no.
There were 2 (TWO) COMPLETELY DIFFERENT 427s in 63.

The first was the Z-11. It was a stroked (only) 409 (from 3.5 to 3.65 stroke). It had TOTALLY different (and not interchangeable with the 409) heads and intake (2 piece intake with different ports/bolt pattern). It is generally accepted 57 were built. It is still a "W" motor, the MARK I. Your mama could have walked into a Chevy dealer and bought one. IT ONLY CAME AS PART OF A PKG IN A 2DR IMPALA (not SS) WITH ALL ALUMINUM FRONT END/BUMPERS. Built to annihilate the competition.

The second was a SECRET, OUT THE BACK DOOR engineering project (generally believed to have been funneled through Smokey Yunnick). THIS is the engine commonly called the "427 Mystery Engine".<-----------<<<< This is where today's BB came from. ONLY hand picked, genuine NASCAR racers (hard core), like Junior Johnson, got these engines. Basically, there is NO documentation on these engines ------- maybe parts for 50 were manufactured. This was the MARK II engine.
When this engine was introduced at the 63 Daytona 500, ALL work came to a sudden halt on the "W" design. And as we all know, the rest is history.
I've said this before. All BB lovers need to drop to their knees and bow to a fresh college nerd (back then) named Dick Kienath------ this was his design. Smokey couldn't believe this dork designed such a work of art!

The MARK III was ONLY on paper.
The MARK IV is our heritage.

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Tom Parsons
 

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Mike:

You can add the 496 (8.1 liter) to the list, as it will be available in 2001 model trucks. It replaces the "tried and true" 454 (7.4 liter), but is supposed to be superior in all aspects.

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Rob Clary
'70 LS-6 Chevelle
Team Chevelle Gold Member #85
Interested in COPOs, Yenkos or other dealer built muscle cars then go here: www.yenko.net
 

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DZ: Yes, you nailed the Mystery Motor. I was trying to stick with "available in a production car" big blocks. And you're right about the Smokester, he liked the Mystery motor, but dislikes the resulting Mk IV. (I don't understand why)

As I understand it, the Mk III was to be the Packard V-8, Chevy was to buy the tooling from the bankrupt Studebaker-Packard Corp, but the deal fell through.

Think about it...The Packard engine has 5" bore centers, while all Chevy big blocks have only 4.8 bore centers. If updated to today's casting technology, and siamesed, we'd have 4.75 bores without too much problem! In fact, the Packard engine wouldn't be legal for NHRA because the bore spacing is too wide. No doubt Chevy would have had to toss the Packard heads, though.
 
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