Longblock? Shortblock?

What's the difference between longblock and shortblock? :confused:
Thanks ...

A short block is the block, crank, rods, pistons, and rings; IE, the "bottom end". A long block is a complete motor including heads, cams, ect.

Originally posted by Someguy
A short block is the block, crank, rods, pistons, and rings; IE, the "bottom end". A long block is a complete motor including heads, cams, ect. And a "turn-key" or "complete" motor includes all the stuff like the intake manifold, throttle body, headers, alternator, etc.
:cool:

i thought a longblock is a large motor, and a shortblock is a small motor :confused:




:p

Originally posted by drift
i thought a longblock is a large motor, and a shortblock is a small motor :confused:

:p
You almost got me. :p

Then whats a bigblock? You always hear about old chevy bigblocks and stuff and Im foreign to muscle car talk. Is a bigblock like a complete chevy engine including duplicates of all the parts stacked on top for WHEN they go and you HAVE to replace them?

So a longblock doesn't include the manifold, throttle body, headers, alternator .. etc???

That makes no sense. Then why don't they call it a full-block and a half-block? :confused:

It's funny how these terms come about sometimes.

Originally posted by integr8
Then whats a bigblock? You always hear about old chevy bigblocks and stuff and Im foreign to muscle car talk. Is a bigblock like a complete chevy engine including duplicates of all the parts stacked on top for WHEN they go and you HAVE to replace them?


big block is a term from muscle cars... for instace, with GM, they had 400ci and larger blocks all based on one block. this was their "big block" lineup. on the other side were the small blocks, aka mouse motors, which are based on the 350 block.

And just to make it confusing you can take a Ford 351 Windsor small block, punk and stroke it out to a 427 which would make it a small block bigger then a 390 big block. ;)


Also it depends on who you buy it from how complete a long block is. Some companies sell "long blocks" which would qualify as what Fritz describes as a "complete" or "turn-key."

The Chevy small block is a specific iron casting and minor variations thereof that has been produced since 1955. It's been produced in displacements from 262 ci to 400 ci. The Chevy big block is a different casting, and has been around from 1965 and has been produced in displacements from 366 ci to 502 ci.

The cool thing is, that since they're all nearly the same block, any part from any small block engine can be swapped from any other small block engine. i.e. You can use any cam made since 1955! This means that not only are there thousands of options, but they're really cheap since there are so many. Same goes for the big blocks.

Ford did the same thing as Chevy. The Ford big block casting (1968) went from 370 to 460 cid, and the Ford small block casting (1962) ranged from 221 to 351 cid.


Drift is right about "complete" v. "longblock" motors - some sellers put everything on a longblock - make sure you know exactly what is and is not included before you buy! In my experience though (mainly with domestic engines) a longblock is generally just the shortblock + heads, valvetrain, and sometimes an oil pan.
:cool:

Well, the 351 is a little different casting then the 302/289 ect. It has a taller deck height, but all the heads, cams, ect are interchangable, besides the lower intake manifold, but that's pretty close.

Originally posted by Someguy
Well, the 351 is a little different casting then the 302/289 ect. It has a taller deck height, but all the heads, cams, ect are interchangable, besides the lower intake manifold, but that's pretty close. Right, same thing with the Chevy's - there have been something like 50 different casting numbers over the last 47 years for the small block - but each shares a massive amount in common with all the others. Mostly the differences are just the different bores sizes and incremental changes, things like moved bolt holes and revised seals or cooling or oil passages.

It's still amazing to me that I can pull a crankshaft from a 1955 chevy pickup truck and put it right into a brand new, 2002 Corvette LS6 engine. The only thing I'd have to add is a rear main seal adapter (which GM themselves sell for about $70) as they slightly changed the rear seal configuration in 1986. Everything else would fit perfectly. Kind of freaks me out. :eek:

:cool:

Just think of all the Millions of $ GM has saved since 1955 on engine development. :D
Also think about how unsafisticated the new LS6 is, especialy when compared with V8s from other Manufactors.
(and dont tell the Corvette owner that the only thing seperating his expensive and very powerfull engine from a 50s pick up are two cylinder heads designed by a small Britsh Enginering shop and occasional car maker. :D)

They shored up the bottom end a bit over the years, but hey. If it works... My boss averages 24 mph city driving in his Corvette. Not too bad for 345 hp.

BTW Fritz, thinking of simple yet effective designs, my car just got back from the shop after its little surgery. :D

Originally posted by Moppie
Just think of all the Millions of $ GM has saved since 1955 on engine development. :D
Also think about how unsafisticated the new LS6 is, especialy when compared with V8s from other Manufactors.
(and dont tell the Corvette owner that the only thing seperating his expensive and very powerfull engine from a 50s pick up are two cylinder heads designed by a small Britsh Enginering shop and occasional car maker. :D)
Well, yes, but I prefer to think of it the other way - the Chevrolet engineers did such a bang-up job in 1955 that there really hasn't been the need to change much in the shortblock. :)

How's 405hp@6000 RPM and 19/28 MPG strike you?
(that's the LS6 - the new Corvette Z06 engine)

How about we compare that to some high-flautin', "safisticated" foreign V8s you seem all hot and bothered about? ;)

Lexus GS430 -> 300@5600 and 18/23
Infinity Q45 -> 340@6400 and 17/25
Jaguar S-type -> 281@6100 and 17/24
Audi A8 -> 310@6200 and 17/25
Rolls Royce Corniche Turbo -> 325@4000 and 11/16
Mercedes E430 -> 275@5750 and 17/24
Mercedes CL55 AMG -> 355@5500 and 16/22
Mercedes E55 AMG -> 349@5500 and 17/24
Mercedes S55 AMG -> 302@5600 and 16/22
BMW 540i -> 290@5400 and 18/24
BMW 745i -> 325@6100 and 18/26
BMW Z8 -> 394@6600 and 13/21
Ferrari 360 Modena -> 400@8500 and 11/16

Hmmm.... Not a single one of these very fine imported automobiles, with all their 'safisticated' technology can beat the LS6 in either power or mileage - and that LS6 has just two valves per cylinder, big 'ol pushrods (no overhead cams), and a block, crank, rods, and pistons that pretty much haven't changed in over forty years.

The Ferrari comes close in hp, but needs to double it's mileage figure. The BMW 740 is almost there in mileage, but needs another 80 hp just to match.

Guess those flat-top haircuts and thick glasses really did something for the engineers back then! :D

:lol2: Im looking at your poor US spec power figures and laughing.

Especialy this one Rolls Royce Corniche Turbo -> 325@4000 and 11/16, (im assuming its the Bently Turbo R) its more like 600+hp, but Rolls will never give you a factory quoted hp figure, thier only statement for the last 40 odd years has been "its enough". :)

As for the other figures care to state your sources? After driving a 540i the other day, and being told by the owner to make sure the traction control works I can tell you it feels like a lot more than only 300hp, but then it is only a 4.4l, and I think if you look at the spefic hp levels, they are both pretty close. :) 71hp per L for the LS6 and 68 for the BMW. :D


However I will admit that you do have a good point, the old Chevy V8s are possibly the longest running single engine design, and the fact that they still continue to provide industry leading power levels (alibit from higher capcity) shows that they still have a lot of life left in them yet.

And didnt the latest Corevette come with a Twincam version of the LS6 with heads designed by Lotus? I know it was intended that all versions of the new Chevy V8 were to be Twincams untill some Market resurche showed most Americans would be opossed to it. So they droped the idea on all models execpt the Corvette, where they were retained to help with the cars modern super car image.

The LS6 uses a single, in-block, hydraulic roller cam with just two pushrod activated valves per cylinder. There is a lot of confusion about this because in 1997 with the introduction of the LS1, GM started marketing it as an "Overhead Valve" or "OHV" engine. It's the same damn thing as it's always been (aka pushrods), but I guess marketing felt they needed to compete with the letters "OHC". Silly.

The cam is billet steel with a hollow center. Block and heads are cast aluminum and the crank is nodular iron (same as any Chevy crank since 1957). I honeslty have no idea who designed the heads, I thought they were just mildly revised LS1 heads, but I'm not 100% sure.

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I got my power specs from www.edmunds.com - this lists the manufacturer's specified hp. aka The marketing number.

I assume that the RR Corniche Turbo is the same as the Turbo R (6.8 liter V8 turbo - 325 hp @ 4000 rpm and 544 ft-lbs. @ 2100 rpm :eek: The LS6 only makes 400 ft-lbs. @ 4800 rpm, so I wouldn't be surprised if that hp number for the RR is correct - it seems to be built to put all of its power down low (after all, peak hp is at 4kRPM!)

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per liter schmer liter. ;) Who the hell cares about output per liter unless you're in a displacement restricted racing class? I posted the MPG numbers as an indication of the engine's efficiency (I know they are modifed heavily by the vehicle it's put in, but they don't exactly publish BSFC for production engines....) Just a guess here, but those other fancy shmancy engine technologies (like Audi's 5valves/cyl) probably cannot scale up to provide that much hp at that level of fuel efficiency (if they could, why haven't they?)

Just for fun, here are some others that are closer in displacement to the LS6:
Mercedes CLK55 AMG - 5.4L V8 - 342 hp @ 5500 rpm and 16/22 for $69k
Mercedes CL600 - 5.8L V12 - 362 hp @ 5500 rpm and 15/22 for $122k
Mercedes SL600 - 6.0L V12 - 389 hp @ 5200 rpm and 13/19 for $130k
Ferrari 456 - 5.5L V12 - 442 hp @ 6250 rpm and 10/15 mpg for $221k
Lamborghini Diablo - 6.0L V12 - 550 hp @ 7100 rpm and 10/13 for $295k

Corvette Z06 - 5.7L V8 - 405 hp @ 6000 rpm and 19/28 for $51k
-- I think it still wins overall. :cool:

* I didn't include trucks and SUVs since their aerodynamics and gearing would be too different to reasonably compare mpg. Prices are rounded off MSRP. All data from www.edmunds.com

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I honestly think that Chevy has a real advantage in the small block. It's been allowed 40 years of research, design, and incremental adjustment and improvement. Rather than trying to harness a new technology from scratch and get it to market within a few years at a resonable cost, the SBC has been able to make itself just a little better each year. After 40 some-odd years, we get something as incredible as the LS6.
:cool:

http://www.chevrolet.com/corvette/images/main/engineering_ls6_major.jpg

And somehow we ended up talking about Chevy's and domestics ... :D :D :D ...

Originally posted by Beyond Imagination
And somehow we ended up talking about Chevy's and domestics ... :D :D :D ...
Well, Chevys vs. imports actually.

And it was because someone asked what a 'small block' and 'big block' meant. :D

The AMG E55 is pretty damn quick. I've been tooling around in my boss's Vette a bit lately (with out him :D) and I don't think he has anything on the E55 as far as straight line speed, despite a weight advantage. I was actually a little disappointed. The 25 mph overall is pretty darn nice with that sort of power though. I just wish it didn't have the CAGS thing. The Z06 on the other hand...

Moppie, the DOHC Corvette your thinking of is the ZR-1 which was available in the C4 Corvette days. Very cool, but horribly expensive. I think the offical reason for dropping the DOHC was it was expensive, adding considerably to the height of the engine and thus cowl height, and besides "we can get the same power and more and flatter torque with our pushrods!" The ZR-1 motor wasn't built by GM either... It wasn't Lotus... I'll remember it about 4 AM I'm sure.

Anyway, the LS6 heads are just basically LS1 heads with larger valves and some re-contouring. The intake and exhaust are also openned up a bit. It really isn't rocket science to get gobbs of power out of that motor.

Short, Long, Big, Small, American, import. Hey its all educational isn't it? ;)

Ahh the ZR-1! I know the heads were designed by Lotus, but not made by Lotus, (since GM has shares in lotus via proton). Lotus looked at useing the engine in the V8 Esprit but decided to design thier own engine instead.

There wern't made by Calloway where they? the German tuning company?
I know they prepare the 300KW versions of the LS2 used in the HSV comodores sold here and in Aussie.

It was Mercury, the marine engine builder, which produced the ZR-1 motor. Lotus could have designed the heads, I don't know.

Calloway did a twin turbo setup and some other stuff for that car here for the VERY upper class car guy.