[Goldenblack440]

Dave, this question is for you mainly, as i remember you said once that the terms "Big Block" and "Small block" were Chev terms...and that our engines are correctly termed A, LA, B, RB, Wedge,Hemi Magnum etc.

But anyone else is welcome to put in their opinion.

Just wondering where or how you heard of this, as this is the sort of thing that almost starts a pub fight. 10 people, 10 different answers etc!

Or was it the Chev motoring fraternity, or the general population that saw that different lines of engines were 'big' and others smaller. As these terms big and small are not words that engineers normally use to describe their precious creations. And it seems to apply to all Detroit engines, Ford, Pontiac Chev etc

A former employee of GM for many years in the production side said he never saw Sb or BB in any GM textbooks or service manual. However they were called that in the GM aftermarket catalogs

so just wondering how you heard this, so i can shut some people up, as i believe it myself as well.

[drewcrane]

Yes that is a good pub fight i mean discussion, my buddie Seth and i have this debate all the time, kinda like what is a muscle car? not alot of facts ,but a ton of opinions

[dave-r]

Chevy brought what we now call the "small block" out in the mid 50s. It was not called a small block then. It was a modern "light weight" wedge head engine that produced a lot of power per cubic inch.

It was a revolutionary engine because Chevy had perfected casting and machining techniques that made the V8 very affordable. It became a big hit and was THE engine to transplant into the Hot Rods of the day. And it still is after all these years.

Chevy also had a large displacement truck engine. It was physically a much bigger block. When big inches were needed for super stock and NASCAR they had to start fitting it into their production cars. It became known as the "big block Chevy". It was after that they started to call the other engine the "small block" so you knew which type of V8 you were talking about.

Once the terms big and small block became the common slang for each type of engine, people started to use the term on other makes. Sometimes with no logic at all. Big block Ford??? What is a 351 then?

With a bit of imagination it was possible to call the LA Chrysler a small block and the B/RB a big block. But there is not really as big a difference in them as there is in the Chevys.

GM is still king in the US motorsport world and Chevy terminology and slang is the common language. For example you hear people refering to the Chrysler LRS axle as a "Posi".

Now you tell me why the chevy engines also became known as the RAT and MOUSE motors. See if you know.

[drewcrane]

was it the 392 hemi was called an" Elephant",and chevy had the mouse motor.and elephants are afraid of mice,i guess a mediphore and it stuck,and the Big block chevys were rat motors,ever heard of the "mouse that roared"?

i kinda remember people talking about these storys, and i did a search and find some truth to it,not being a GM guy i never paid attention

[Goldenblack440]

Thanks for the answers guys, esp Dave, that's just what i was looking for. So difficult to find good, hard facts on forums...much is hearsay, opinion and often B.S. I did hear that Chev was the first to produce 1hp per cube, with the 283, well that's what i heard from a Chev hed anyway. Great bit of history there Dave ...yeah the 351C is in between, not really classifieable, whereas the 302/351W is a true "small block" 60 deg V. If you have ever seen a Windsor block upside down compared to an LA engine, you will see how small they really are. But they had class too. regards

[Goldenblack440]

PS, Drew, i'm not sure that Elephant, as in the Hemi, had anything to do with mouse...only my guess, which has zero foundation. I actually thought the elephant term was coined by Mopar guys for the new 426H, due to its massive size in the eng bay.

[dave-r]

PS, Drew, i'm not sure that Elephant, as in the Hemi, had anything to do with mouse...only my guess, which has zero foundation. I actually thought the elephant term was coined by Mopar guys for the new 426H, due to its massive size in the eng bay.

Correct. It was the 426 that was called the Elephant motor. It was much bigger than the old style hemi which was more like the old 318 poly block complete with rear mounted distributor.

The Chevy big block was called The Rat by Drag racers because it used studs to hold the heads on and between rounds at the track, with the heads removed, the block looked like some sort of spiky animal. Like a porcupine.
Rednecks tend to call any kind of vermin "Rats" so the block got that nickname. American nicknames don't always make sense. Like "blowjob". How confusing is that?

If the big block was known as the rat then it followed that the smaller engine should be called the Mouse. At least that bit is logical.

[drewcrane]

Ok lets open this up, Pontiac used the same block for all there motors (except 301)

also AMC used the same blocks for all there motors ,

so AMC only used small block dimensons, 290, 360, 390 ,401

to me its about weight ,and dimensions not necessarily CID right?

even though most big block motors have more cubes,

there are alot of small cubed big blocks

, and these days there are alot of small blocks with larger cubes

[dave-r]

I go by the effect of dropping one on your foot.

Smashed bones but foot still basically recognisable as a foot = small block.

Nothing but a grease spot were your foot used to be = big block.

Well it is as good a definition as any isn't it?

[Eddie]

Interesting. After reading all this I take it a 'blowjob' should be called a slippery meatpole wanking! The 354 Hemi with 2 fours made 355 HP per cubic inch. I believe this was the 1st 1/HP per cube mass produced normally aspirated U.S. engine. Not the Boat anchor 283

[dave-r]

Yes but that Hemi was very expensive to produce compared to the Chevy lumps which could make as much power per cubic inch for much less cost.
Chrysler stopped producing the hemi head engine in the late 50s and developed their own cheaper and more powerful wedge head engines for that very reason.

[drewcrane]

Yes but that Hemi was very expensive to produce compared to the Chevy lumps which could make as much power per cubic inch for much less cost.
Chrysler stopped producing the hemi head engine in the late 50s and developed their own cheaper and more powerful wedge head engines for that very reason.

so just who invented the hemi head? ford?

[dave-r]

Hemispherical cylinder heads have been used since at least 1901.

They were used by Welch in 1904, the Belgian car maker Pipe in 1905, the Peugeot Grand prix Car of 1912, the Alfa Romeo GP car of 1914, Daimler, and Riley.
The hemi head was the design of choice for Duesenberg, Miller and Offenhauser.
Stutz built four valve hemi head engines, conceptually anticipating modern car engines. The BMW double push rod design, taken over by Bristol Cars, the Peugeot 403 and the Toyota T engine are other well known hemi engines.

Chrysler used the Hemi head in the 50s primarily because after the War the available fuel was very poor quality and low octane. In order to get a decent compression ratio and volumetric efficiency (i.e. power) they did tests on various head designs. One of which was the British Austin Healey. Chrysler engineers found this little engine was the highest powered and most efficient of all the designs they tested. So they designed a head to mimic that.

Being expensive to produce it was dropped in 58/59 in favor of the cheaper wedge design and only brought back in 1964 as a race engine upgrade to the 426 Max wedge.

[ianandjess]

i may be wrong but i was under the impression that they first appeared in a riley
cheers ian

[dave-r]

i may be wrong but i was under the impression that they first appeared in a riley
cheers ian

Possibly. But Riley didn't really start producing 4-wheeled cars until 1905. The only thing known about the earlier 3-wheeled vehicle Riley built was that it featured the very first mechanically operated intake valve. Until then they opened with suction from the piston.

[Eddie]

I always thought the Hemi head or crossflow head was first used in a Belgian Pipe Co. engine too. There IS a difference between the Pentroof Hemi Head of which modern as well as some vintage designs of which you described, and the Chrysler Hemi head. Both designs have only 1 thing in common, they are crossflow in the intake and exhaust tracts. The chambers are different in the fact that the Pentroofed 'Hemi's have a shallow chamber and a much shorter piston allowing quicker revs. They are also used in Multi-Valved Heads. The Chrysler design incorporated as much existing tooling as possible to make production as well as the poor gasoline quality as Dave mentioned. The Pentroofed design is widely used in a lot of production cars and trucks, motorcycles ectt today. It gains most of the attributes of both the crossflow designs as well as efficiency due to a smaller chamber. The Chrysler, Ford, Ardun designs allowed more chamber volume which in turn allowed way more fuel/air to be packed in the chamber like in supercharged race engines without possible hydrolocking when the fuel volume was great and Nitro was used. At least thats the way I see it. The 5.7/6.1 is still a dual rocker shaft engine like the traditional Hemi's but use a shallow much smaller chamber due to emissions concerns. It's not a true "Hemi" or a Pentroofed design. Small chambers produce less HydroCarbon emissions.

[drewcrane]

OK its really hot here (37.777) and seth and i are just waiting for it to cool off,so were bored, and seth wants to know, dave if you know what the ferrari big blocks ,and small blocks ,what were they called,and what was nominal displacement of said engines?


Seth has a prize of a sombrero and a green card

[fal308]

So does this mean I need to send Eddie my 354 Hemi to get built?
Though my cam is more for low end torque rather than high end horsepower.