Discussion
Depends what make. A Ford 426/7 in is a big block. So is the 390 in 60's onwards Fords.
The 7.0 in a modern Corvette is still a small block, and in the aftermarket crate engine world, think it's possible to go to 454ci small block chevy's.
Someone will probably be along with a more in depth reason, but I think more to do with physical size of the engine than the capacity.
HTH
The 7.0 in a modern Corvette is still a small block, and in the aftermarket crate engine world, think it's possible to go to 454ci small block chevy's.
Someone will probably be along with a more in depth reason, but I think more to do with physical size of the engine than the capacity.
HTH
Edited by Motown Junk on Monday 3rd November 16:54
Edited by Motown Junk on Monday 3rd November 16:55
454ci Small Block:
http://www.hotrod.com/techarticles/engine/113_0307...
Any donations to the cause, greatfully accepted
http://www.hotrod.com/techarticles/engine/113_0307...
Any donations to the cause, greatfully accepted
Whether it's small or big block depends on the family of engines the engine belongs to hence the LS7 7.0 remains a small block as it's derived from the LS1/2/3/6 5.7/6.0
As a rule of thumb using the most popular sizes - 200ci = 3.3; 281ci = 4.6; 305ci = 5.0; 350ci = 5.7; 400ci = 6.6
Chevy small blocks were referred to as "Mouse" motors while the big blocks were "Rat" motors.
As a rule of thumb using the most popular sizes - 200ci = 3.3; 281ci = 4.6; 305ci = 5.0; 350ci = 5.7; 400ci = 6.6
Chevy small blocks were referred to as "Mouse" motors while the big blocks were "Rat" motors.
LuS1fer said:
Whether it's small or big block depends on the family of engines the engine belongs to hence the LS7 7.0 remains a small block as it's derived from the LS1/2/3/6 5.7/6.0
As a rule of thumb using the most popular sizes - 200ci = 3.3; 281ci = 4.6; 305ci = 5.0; 350ci = 5.7; 400ci = 6.6
Chevy small blocks were referred to as "Mouse" motors while the big blocks were "Rat" motors.
Was waiting for someone to say that..As a rule of thumb using the most popular sizes - 200ci = 3.3; 281ci = 4.6; 305ci = 5.0; 350ci = 5.7; 400ci = 6.6
Chevy small blocks were referred to as "Mouse" motors while the big blocks were "Rat" motors.
Just to expand a little, the reason you get larger capacity 'small blocks' is because of newer trend of fitting longer stroke cranks, boring out and taller block heights to achieve larger capacity without the bigger engines weight or size. So these new increased capacity small blocks often exceeds the smaller 'big blocks'
ie. a stroked and bored small block will be 400+ cubic inches, standard smaller big block is 396.
Most makers, Ford, Chevy, Mopar have a range of small and big block engines of varying sizes..
Given the responses so far about same size small block but increased stroke (is it increased piston diameter at all?) clearly the same can be done to the big block in which case what is the biggest big block available today & what is the biggest big block available in all time?
Finally does the fact that the small bock can be increased to x cui mean that essentially the big block will soon be extinct? Like for like i.e. say a 396cui big block vs a 396cui small block power wise?
Finally does the fact that the small bock can be increased to x cui mean that essentially the big block will soon be extinct? Like for like i.e. say a 396cui big block vs a 396cui small block power wise?
The small and big block distinction is cars is mainly historic, before engines achieved modern levels of efficiency. If there are still big blocks, they are probably for commercial applications.
There is a German Cobra replica which has a 9.x litre engine which I assume is a big block. Not sure how big they get.
There is a German Cobra replica which has a 9.x litre engine which I assume is a big block. Not sure how big they get.
Welshbeef said:
Given the responses so far about same size small block but increased stroke (is it increased piston diameter at all?) clearly the same can be done to the big block in which case what is the biggest big block available today & what is the biggest big block available in all time?
Finally does the fact that the small bock can be increased to x cui mean that essentially the big block will soon be extinct? Like for like i.e. say a 396cui big block vs a 396cui small block power wise?
Yes, bore is increased sometimes for capacity, but only as far as the block/liners allow.. Largest big block i've seen (on a road car) was a 572ci, which is 9.3 litres ! I think some of the drag cars run even bigger Hemi type alcohol engines..Finally does the fact that the small bock can be increased to x cui mean that essentially the big block will soon be extinct? Like for like i.e. say a 396cui big block vs a 396cui small block power wise?
People that run 396 big blocks are usually for originality or convenience of what they came in (late 60's vettes, camaros etc..) or cos the'yre relatively cheap now..
Welshbeef said:
That last post has just raised another question.... what is a Hemi?
Also are all the V8's pushrod? I recall reading something along these lines and it still amazes me that the vette C7 is like that.
Ooh, that's opened up a whole new can of worms...Also are all the V8's pushrod? I recall reading something along these lines and it still amazes me that the vette C7 is like that.
Hemi refers to the hemisperical head design used by some manufacturers, I'm not that clued up on Hemi so I hope a more knowledgable person will chirp in...
"most' yank V8's are pushrod, and it's stayed that way cos it works fine ! many European, Italian supercar, and Japanese V8 engines are not pushrod. Remember the Corvette Zr1 of 1990, that was a 4 overhead cam 48 valve engine, but it proved expensive to produce, and was a very wide so would have ben hard to fit in the new Corvette, so was dropped.
A Hemi has a hemispherical combustion chamber which allows for bigger valves and more power. As I understand it, the new Chrysler Hemi isn't actually a true hemi.
Engines have evolved from flatheads to side-valve to overhead valve operated by pushrods to overhead cams which eliminate pushrods but with the advent of twin cam engines. the weight moved to the top of the engine and raised the centre of gravity (less so in a V or a slant or flat four).
While European cars moved to ohc to improve the power outputs of small and often arthritic engines, the Americans with their six and eight cylinder engines didn't need to because being low-revving, high torque engines, they didn't suffer from the valve bounce that little engines did because they all had fairly low rev limits and auto boxes.
Ford abandoned the pushrod with the 4.6 modular engine that replaced the 5.0 in the early 90s Mustang and moved to sohc in the GT and dohc for the Cobras. Meanwhile, Chevy experimented with the ZR1, a quad cam engine built by Lotus that produced a heady 385hp and then 405hp but the fact was that a ZR1 cost twice what a stock Corvette cost. The 300hp LT1 was less peaky and produced strong grunt at the bottom end which is what Americans loved. In the real world, it was as fast as a ZR1 in everyday use. It was this that really led to the demise of the ZR1 plus the fact that a good pushrod costs a dollar to service compared to the ZR1.
While Ford switched to ohc, GM pushed on with development of the pushrod which offered major benefits in being physically smaller and lower, using a single cam instead of two or four and was therefore lighter. Having the cam in the V meant the top end of the engine was lower so the engine could be mounted lower and further back. On the 4th gen Camaro, the rear two cylinders are behind the windscreen.
The LS1 marked the switch from iron to all-alloy but still retained a simple 2 valve per cylinder layout and it was clearly far cheaper to produce than an exotic quad cam 32v ZR1. Suddenly, the C5 had 350hp and the Z06 soon bumped that up to 405hp. GM, just as Mazda had done with the rotary, had proved that the pushrod could be a world class engine in terms of power, performance and economy and above all, it was cheap to make and could fit a huge variety of cars in terms of packaging. It also kept the price down. The old bugbear of pushrods, lack of high rpm ability, was solved through better and lighter pushrods and more efficient valvetrains.
People often think that GM only produce pushrods but they don't. The Cadillac Northstar V8 is a quad cam 32v V8 used in the Caddys which are more expensive, including the XLR which is a restyled Corvette. Even when supercharged, they still produce less power than the Corvette engines which are probably a little less refined in comparison.
The new Chrysler V8s are also ohc and only GM have pushed the pushrod to it's ultimate form. They even toyed with a square four engine at one point, again trying to find an engine that was compact but I guess that one never went anywhere.
The Americans aren't slow to adopt technology either. The 2005 Mustang V8 got 3v per cylinder and variable cam timing and the Chryslers use cylinder de-activation to achieve better economy.
Engines have evolved from flatheads to side-valve to overhead valve operated by pushrods to overhead cams which eliminate pushrods but with the advent of twin cam engines. the weight moved to the top of the engine and raised the centre of gravity (less so in a V or a slant or flat four).
While European cars moved to ohc to improve the power outputs of small and often arthritic engines, the Americans with their six and eight cylinder engines didn't need to because being low-revving, high torque engines, they didn't suffer from the valve bounce that little engines did because they all had fairly low rev limits and auto boxes.
Ford abandoned the pushrod with the 4.6 modular engine that replaced the 5.0 in the early 90s Mustang and moved to sohc in the GT and dohc for the Cobras. Meanwhile, Chevy experimented with the ZR1, a quad cam engine built by Lotus that produced a heady 385hp and then 405hp but the fact was that a ZR1 cost twice what a stock Corvette cost. The 300hp LT1 was less peaky and produced strong grunt at the bottom end which is what Americans loved. In the real world, it was as fast as a ZR1 in everyday use. It was this that really led to the demise of the ZR1 plus the fact that a good pushrod costs a dollar to service compared to the ZR1.
While Ford switched to ohc, GM pushed on with development of the pushrod which offered major benefits in being physically smaller and lower, using a single cam instead of two or four and was therefore lighter. Having the cam in the V meant the top end of the engine was lower so the engine could be mounted lower and further back. On the 4th gen Camaro, the rear two cylinders are behind the windscreen.
The LS1 marked the switch from iron to all-alloy but still retained a simple 2 valve per cylinder layout and it was clearly far cheaper to produce than an exotic quad cam 32v ZR1. Suddenly, the C5 had 350hp and the Z06 soon bumped that up to 405hp. GM, just as Mazda had done with the rotary, had proved that the pushrod could be a world class engine in terms of power, performance and economy and above all, it was cheap to make and could fit a huge variety of cars in terms of packaging. It also kept the price down. The old bugbear of pushrods, lack of high rpm ability, was solved through better and lighter pushrods and more efficient valvetrains.
People often think that GM only produce pushrods but they don't. The Cadillac Northstar V8 is a quad cam 32v V8 used in the Caddys which are more expensive, including the XLR which is a restyled Corvette. Even when supercharged, they still produce less power than the Corvette engines which are probably a little less refined in comparison.
The new Chrysler V8s are also ohc and only GM have pushed the pushrod to it's ultimate form. They even toyed with a square four engine at one point, again trying to find an engine that was compact but I guess that one never went anywhere.
The Americans aren't slow to adopt technology either. The 2005 Mustang V8 got 3v per cylinder and variable cam timing and the Chryslers use cylinder de-activation to achieve better economy.
Edited by LuS1fer on Thursday 6th November 14:52
Mustang 4v unit:
Corvette LS6 engine:
Chrysler Hemi engine:
Oh and I was wrong about the new Hemi being ohc, it is in fact a pushrod albeit "evolved" to place the cam higher in the block to shorten the valve lifter mechanism.
http://www.allpar.com/mopar/new-mopar-hemi.html
The Cadillac Northstar engine perhaps shows how bulky a DOHC V8 can be in comparison:
Corvette LS6 engine:
Chrysler Hemi engine:
Oh and I was wrong about the new Hemi being ohc, it is in fact a pushrod albeit "evolved" to place the cam higher in the block to shorten the valve lifter mechanism.
http://www.allpar.com/mopar/new-mopar-hemi.html
The Cadillac Northstar engine perhaps shows how bulky a DOHC V8 can be in comparison:
Edited by LuS1fer on Thursday 6th November 15:09
Wow - without the OHC/DOHC those V8's are very compact.
In the UK If I wanted a Corvette - fairly modern - what sort of prices are they 2nd hand? And what power & finally what MPG/6th @70mph - or top gear @70mph?
I recall following a C5?? at M4 J8/9 towards High Wycombe - Me in 3rd at 60mph coming off the round a bout him in front he nails it me too - all the way in 3rd & 4th the noise of the V8 was very very nice and the smell of slightly unburnt fuel & the heat from it was great (only draw back was either he wasnt giving it everything - or my expectations at how much faster/gaining ground over mie at those speeds it would be (it was a red one BTW)
In the UK If I wanted a Corvette - fairly modern - what sort of prices are they 2nd hand? And what power & finally what MPG/6th @70mph - or top gear @70mph?
I recall following a C5?? at M4 J8/9 towards High Wycombe - Me in 3rd at 60mph coming off the round a bout him in front he nails it me too - all the way in 3rd & 4th the noise of the V8 was very very nice and the smell of slightly unburnt fuel & the heat from it was great (only draw back was either he wasnt giving it everything - or my expectations at how much faster/gaining ground over mie at those speeds it would be (it was a red one BTW)
The early C5s made 345hp. Later ones went up to 350hp. Euro-C5s were officially claimed to be 339bhp - you can recognise them by the rear bumper-mounted foglamps and reversing lights incorporated into the rear light clusters.
Autocar tested an early automatic C5 and got 0-60 in 5.7 and 100 in 13.1 but these may be from a well-used Press car as I've never seen figures that slow (even the Camaro Z28 racked up 5.4/13.0). A manual C5 tested in 1998 achieved more typical 5.3/11.9. Certainly the US mags rack up faster times on later cars of 4.8 seconds.
The fastest of the C5 breed is the booted Z06 which ran from 2001 (385hp) to 2004 (405hp and a heads-up display for latter 3 years). The Americans racked a 0-60 of 3.8 but more typically it's low 4's. 100 comes up in around 9 seconds.
The Corvette is geared to reach it's maximum speed of over 170mph in 5th and 6th is an overdrive.
MPG will depend on how you drive it. My Z28 which used the same LS1 engine and which is heavier achieved about 20 commuting to Cardiff and back from Caerphilly. The Corvette Z06 was a little better and did about 24. Both will do over 30 on a steady cruise. Remember the display calculates in smaler US gallons.
Prices vary. I've seen them as low as £12k, possibly even less but bear in mind that as the dollar strengthens and the exchange rate drops, the prices always firm up and may even go up. A Z06 will cost anything from £20k up but as with miost American cars, buyers are limited and prices are very negotiable.
The strength of the Corvette is it's running costs. They are a cinch to service and basically just take oil changes and occasionally brake pads. My mate has his serviced at Yapps in Llanishen but I used to do my own because it's so simple. He's spent almost nothing on his over the past 3 years, not least because the car tells you when it needs to be serviced and it's a long time coming....
You also only pay £185 per year for imported and pre-2001 cars although the later cars are better. It's Chevy's way to improve cars year on year so the later the better.
This one is low miles. Not mad on the colour but electron blue didn't come along until later: http://www.pistonheads.com/sales/769355.htm
There's a yellow Z06 on there for £18k too.
Autocar tested an early automatic C5 and got 0-60 in 5.7 and 100 in 13.1 but these may be from a well-used Press car as I've never seen figures that slow (even the Camaro Z28 racked up 5.4/13.0). A manual C5 tested in 1998 achieved more typical 5.3/11.9. Certainly the US mags rack up faster times on later cars of 4.8 seconds.
The fastest of the C5 breed is the booted Z06 which ran from 2001 (385hp) to 2004 (405hp and a heads-up display for latter 3 years). The Americans racked a 0-60 of 3.8 but more typically it's low 4's. 100 comes up in around 9 seconds.
The Corvette is geared to reach it's maximum speed of over 170mph in 5th and 6th is an overdrive.
MPG will depend on how you drive it. My Z28 which used the same LS1 engine and which is heavier achieved about 20 commuting to Cardiff and back from Caerphilly. The Corvette Z06 was a little better and did about 24. Both will do over 30 on a steady cruise. Remember the display calculates in smaler US gallons.
Prices vary. I've seen them as low as £12k, possibly even less but bear in mind that as the dollar strengthens and the exchange rate drops, the prices always firm up and may even go up. A Z06 will cost anything from £20k up but as with miost American cars, buyers are limited and prices are very negotiable.
The strength of the Corvette is it's running costs. They are a cinch to service and basically just take oil changes and occasionally brake pads. My mate has his serviced at Yapps in Llanishen but I used to do my own because it's so simple. He's spent almost nothing on his over the past 3 years, not least because the car tells you when it needs to be serviced and it's a long time coming....
You also only pay £185 per year for imported and pre-2001 cars although the later cars are better. It's Chevy's way to improve cars year on year so the later the better.
This one is low miles. Not mad on the colour but electron blue didn't come along until later: http://www.pistonheads.com/sales/769355.htm
There's a yellow Z06 on there for £18k too.
Edited by LuS1fer on Thursday 6th November 16:26
If you're talking about an earlier Corvette like the C4, these tend to be fairly cheap - anything from £5k to £10k. They are, in my view, far more fun than a C5 as they are a bit of a hooligan's car. However, the build quality isn't as good as the C5 and you do need to go round tightening screws periodically where they rattle loose. They are also far more prone to leaking. Avoid the crossfire 1984 cars. The Tuned Port Injection cars are far better but are obviously getting old now and, being worth not very much, tend to be less looked after.
It's a bit of a quandary engine-wise. The iron-block L98s were fitted between 1985 and 1991. The 1991 got the later facelift but not the later LT1 engine. They made 235-250hp. The 1992 model year came with the infamous 300hp LT1 which removed the distributor and put a dinner-plate direct-drive Optispark on the end of the crankshaft. They can be problematic as they're in the line of fire from water. I'm not saying they're not reliable but they can have problems and can be expensive to replace.
Good fun at the right price much like TVRs but a C5 was a quantum leap forward after a 12 year run. I had a 1985 model when it was 9 years old and ran it for 3 years without any problems at all and that was a daily driver. It did leak though.
BTW, what car were you in when behind that Corvette? My work stops me clicking on your profile.
It's a bit of a quandary engine-wise. The iron-block L98s were fitted between 1985 and 1991. The 1991 got the later facelift but not the later LT1 engine. They made 235-250hp. The 1992 model year came with the infamous 300hp LT1 which removed the distributor and put a dinner-plate direct-drive Optispark on the end of the crankshaft. They can be problematic as they're in the line of fire from water. I'm not saying they're not reliable but they can have problems and can be expensive to replace.
Good fun at the right price much like TVRs but a C5 was a quantum leap forward after a 12 year run. I had a 1985 model when it was 9 years old and ran it for 3 years without any problems at all and that was a daily driver. It did leak though.
BTW, what car were you in when behind that Corvette? My work stops me clicking on your profile.
Edited by LuS1fer on Thursday 6th November 16:01
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