its interesting that you rolled your eyes at my comment, and didn't mention anything about efficiency in your entire paragraph, or contest the fact that they're heavy.

I didn't say anything about the cost of building a BBC. I'm sure if you know what you're doing they can be built for a reasonable amount. I also don't remember saying anything about them making power. Obviously something with a 450+ cubes is going to get you into the 12's pretty easily.

As far as a BB being heavy, they are, and a SBC car will always outhandle an equally set up BB car. That's one of the reasons I tend to like SB motors.

lastly, BB motors are anything but efficient. That said, however, I don't think anybody who builds one really is worried about that. They're big, old school motors that are heavy with a lot of big heavy parts. They use a lot of fuel, I don't think anybody would deny that. By todays standards they probably do use more fuel per unit of power than most newer engines. You see, that's what efficiency means . Cost of input per unit of output.

K

I understand what your saying and honestly do not mean to step on your toes... I mean that sincerly too... Different views are always going to be the rule and that very well understood...

My main issue is with a heavy car or truck the sheer torque and HP that a BBC makes does the trick... If it were a light car or truck then a nice tricked out SBC would do fine... I`ve always built and loved SBC`s also (25+ years) but have slowly moved to and found that BBC`s have something their little brother just does not have... "Clout" a Rat is most always scarer than a mouse...

To address the weight issue... There is barely 150 lbs between the cast iron versions check here and you will see... Also add alum heads to a BBC and it goes on a very nice diet... But speaking of diet any hotrodder also knows that fuel economy and HP do not go together for the most part... For the cars and trucks of the late 60`s & early 70`s the big engines are what make up that era and what they are noted for... I could just as easy put a 5.3 LS1 type motor in my 69 C10 go with the hot cam and even a 4L60E to counter the 4.56 gear I have... BTW I have one of these engines with 34 miles on it just sitting in the garage... After seeing what was out there and noticed everyone had a SBC in their older truck like mine I went with what I knew would make heads turn and the bud`s drool... I had the choice of a 3rd gen mouse but a Rat has a soul and its nasty point blank...



BTW with a BBC in my truck the value went up dramaticly too (think that is efficiency)...? Also the above qoute almost has a ricer tone...? Old school is cool...


One last thought... Dynamite comes in small packages (true)

But Bombs come in crates...(very true)

I like "big heavy old school parts"
Seems like everything was better made back then. My equation is Lighter=Cheaper=Flimsier=****tier. There aint nuthin that sounds like a big block!

Your equation lacks the additional expense of "working" a small block to produce the same power that the BB produces "out of the box". When your done you have a small block "close to the edge" of its ability. The BB is not even breaking a sweat, since it had the HP to start with.

But your main point was they are "inefficient"
If you massage the BB with the exact same treatment you gave the SB. What would the SB efficiency advantage be due to?

No sir that is not correct... if the resistance in the loop is the same then current goes up with voltage. OHMS law says

I X R = E ....... I = amps, R equals resistance and E = electromotove force which is voltage.

so E / R = I
12 volts divided by 4 ohms is equal to 3 Amps
24 volts divided by 4 ohms is equal to 6 amps

see that by using simple algebra, the voltage; E or current; I is always on top of R , resistance, thus resistance is Inversely proportional to both voltage and current, which would therefore make E and I , proportional...simply stated this means if resistance stays the same and wither Voltage or current goes up then the other must also go up.

if voltage doubles in an AC or DC circuit so must amperage, it's ohms law, look it up.
If resistance remains the same. Resistance in a length of wire does not change.
Voltage is proportional to Current and inversely proportional to resistance, that's why they call it Resistance. It resists a change in current.

It's like a water facet. Voltage is the pressure available Like torque, even with the facet off. Current is like the flow of water, only it's electrons. That's like after you turn the water on. ( Like HP, now you have something to measure the work being done ) Resistance is like the water hose..... it holds back flow due to internal friction. Like the internal friction of a motor.

don't believe me do a search on Ohm's law. Or torque.... or physics.....
natural laws of nature.

High power transmission lines are not low current, if they were they would be safe to play with. You ever notice those very large MICA or glass insulators that they use to isolate them from the WOOD? Why would they want to isolate them from wood if they were low current? Wood is a pretty good insulator. just not good enough when 1000 amps is rolling through it. It takes .1 amps or 100 MilliAmps to stop the human heart. SAFETY is why they step it down to 240 VAC to go in your house.

sorry to bust your bubble man but if a high power transmission line has to carry 500 homes with 200 amp service entrys .....it is NOT low current. Some people's lights dim when their AC unit kicks on. That is a result of a temporary max load of the X former on the pole, the line recovers quickly as the motor capacitor charges back up.

A step up or down transformer ( step up to high voltage ) is used to COMPENSATE for the extremely LONG transmission lines used in distributing power. All you need is 240AC or in some case industry needs 3 phase 480. BUT if they put that on the lines it would deteriorate badly due to the resistance of the extremely long transmission lines. Although wire doesn't have much resistance, the longer it is the more it has, therefore they use step up transfomers at sub stations to step up the voltage, then they step it down again at the tranfomers located on the pole in your neighborhood.

Step down transfomer, two inductors submerged in oil, generally wound around a metal core. When lines of electromotive force are sent through a piece of wire wound around a metal core, they can induce ( inductor ) voltage or lines of EMF around the core, now if you "center tap" the wire OR even better, like an automotive coil use a secondary coil opposite of the primary, you can induce voltage in that secondary. Now you can "adjust" the voltage in the secondary by the number of windings Or where you "tap" it. An inductor tends to resist changes in current, while a capacitor tends to resist a change in voltage. Hence the old term used for a inductor was a "choke" since it resisted changes in current. This also works to the advantage of the power company.

They have somewhat of an abundance of current available at the primary for each neighborhood transfomer, you might load the secondary of the transfomer if several motors come on at once, but you won't load their lines. The dimming of lights that you see is the temporary voltage drop since the transfomer will try to maintain current.... however it recovers quickly.
since plenty of voltage and current are avialable at the primary.

Not trying to be a smart *** here bro but trust me on this one....

Hey you did get part of it right, they do it to prevent power loss.


sorry for the Hi jack... I dunno about this 454, 427, small block argument but i will say this, there is NO RULE in ANY motor sport on how small you can build an engine, there are literaly 1000's if not more rules on how large you can build an engine. bigger isn't always better BUT in the case of torque and HP it is. When they decide to put a motor on a ship, they use very large bore ( 11-12 inch ) engines, not 350 chevys. nuff said.

To me these have holes in them... First of all I dont think he meant low current as in safe by any means... Also the step down transformers from the line do infact increase the current just like a welding machine does... It inversely raises the current while the voltage goes down... Also its very simple to point out that the high voltage line is not carrying a large amount of current as it would simply melt with as much as your suggesting or we would have cables the size of huge pipes... Also the dimming of the lights means you either have an to small of a service or it has a bad connection or the service coming in... The main reason I dissagree is I used to work with linemen & electricans at my job and tended to pay attention...


But back on track its just a personal choice about the 427 or 454... My next project should be a 496 stroker (internaly balanced if possible)

I have electral blueprints here if anyone wants to study them.

People here are comparing an engine to an engine when they need to be comparing an engine to an application.

Gobs of off idle torque do you no good if you can't hook it to the pavement. You end up pedaling the throttle until it hooks. That equals wasted power in my opinion.

HA HA! Sorry to bust YOUR bubble !
I guess you only know 1/2 of ohms law. Heres the rest of it:
Power=Voltage*Current OR Power=CurrentSquared*Resistance;

POWER=WATTS! I use P or W interchangeably here:
The subject is POWER! Thats what engines make and so do electrical stations!
Just like a transmission in first, reducing the speed of the engine steps up the power, but reduces speed. Shifting increases speed, but reduces power. This is fundamental physics. Power is what moves things, power is what does the work.
"Don't believe me do a search on Ohm's law. Or torque.... or physics..... natural laws of nature."


Just like a transmission, if you step up voltage with a transformer, you step down current. Since power=voltage*current, using basic algebra you can see they ARE INVERSLEY PROPORTIONAL.
This is basic electricity 101:
http://wolfstone.halloweenhost.com/...ansformers.html

To understand why the transmission lines don't simply carry 240VAC I'll use simple numbers to easily demonstrate the math:
Lets assume a high tension line conatains 240VAC and serves 100 users at 240Amps each, (100user*240Amps each) thats 24,000Amps! Using ohms law P=V*I, the POWER generator is supplying 5,760,000 Watts into the system. Now say that the wire carrying this current measures 1 ohm. Since V=I*R, the transmission line will drop (24,000A*1Ohm) = 24,000 VOLTS due to the resistance of the wire. (which leaves nothing left and is impractical) All the POWER (Isquared*r)= 24000A*1Ohm=5,760,000Watts!) will be dissapated in the wire.

Now lets say I step up with a transformer to 24,000Volts at the transmission source, to supply the same POWER to the users (5,760,00W) the current is reduced to 240 Amps; (P/V=I)=(5,760,000W/24000V=240A). So at the end of the line, the transmission wire has now only dropped 240V, out of 24,000 (V=I*R). Only a fraction of what was sent, as opposed to ALL of it in the previous example. But your home can't use 24,000V. So now you use a step down transformer, to step down the 24,000 volts to 240V (and step up the current due inverse relationship ) for the 100 homeowners who can now draw 240Volts at 240 amps. (240V*240A=5,760,00W). I did not include the 240Volt loss in these calculations to keep the math simple, but as you can see, losing 240V out of 24,000 will not impact the math too much. For fun, if the wire is carrying 240A and measures 1 ohm (P=Isquared*R)=(240*1)=240Watts. The transmission line is NOW only dissapating 240Watts out of 5,760,00 watts being put into the system! The rest of the 5.7MW is going to the loads. The point is that by stepping UP the voltage, thereby stepping DOWN the current, I am able to deliver the same 5.7MW to the loads, without losing all the power in the transmission line.

All these transformers are used to to minimize the voltage drop, caused by the power lines disappating the power due to thier resistance. Higher voltage allows LOWER current through the transmission line. But the high voltage is not usable by the consumer, so they step it down to what you need.

THAT, my friend, is the reason for power distribution transformers (and trasmissions too )
"Not trying to be a smart *** here bro but trust me on this one....
Hey you did get part of it right, they do it to prevent power loss."

BTW: The mica insulators are used because the have a extremely high dielectric constant. Way higher than wood. They are needed due to high VOLTAGE not high current! At these high voltages even the resistance of AIR comes into play. Don't believe it? That's why those tall mallory coils have the extra length and insulator so the high voltage (low current) spark can't jump across the tower. It has absolutley nothing to do with current!

Good point Lonestar...

Certainly the planned 496 will not be going into the 69 C10 but an all out drag car... The 427 I have still has way to much torque for reg street tires as I use Hoosier DOT slicks and soft rear springs (coil spring factory long arm type rear suspension) but it does bite hard and will jump almost anything off the line... 0 to 60 in 4.4 seconds for a full size truck is alot better than spinning your wheels...

If I didn't have to disect electrical plans for our developments all the time, I would give you all the specifics.

How about we get this thread back on subject?

Some say go with a 454 (bigger is always better) and some say 427. Why doesn't everyone explain how there opinion applies directly to his application in a 3,000 Corvette.

I say if I go with the "bigger is always better" attitude then I suggest using an 8,000 HP Top Fuel Nitro burning engine. That ought to do the trick.

For some reason I don't think the 'Vette would get too far but I could be wrong...remember, bigger is always better.

In real life, you can't use more power than the car is capable of handling...any more just slows you down (Top Fuelers don't seem to win much when they break the tires loose).

This is why I say to go with the 427, periodically correct and more than enough power to do the job...any more would just slow the car down.

That is the reason why I was asking what transmission and what rear gear was in the Vette. A 454 will drive a 3.08 gear much better than a 427. That 1/4" of stroke does wonders, just like the extra stoke in a 383 as compared to a 350.

The 454 is much more versitile than a 427. It can be set up with great low end torque to pull a 3.08 automatic or can be setup up to run higher rpms with a 4.11 4 speed or anything in between.

The low end torque of the 454 can be moved up the power band with a bigger cam and/or wider lobe centers. I'm sure a mild cam 427 will make more low end torque than a 454 with a longer duration cam or even a long duration 496. So the power band is mainly determined with the cam. If you don't what low end torque for some reason then install the right cam for the application.

Good points.

He also wants periodically correct.

One problem, you start running a highway gear in a light car and it will never quit spinning the tires with that amount of torque.

first of all you said LOW current. and now you're repeating what I said about the insulators. no **** I * E does equal W

second of all you said the SAME dahm thing I did about power lines having resistance. dahm any moron who knows ohms law knows that the longer a line is the more resistance is in it. You attempt to take me to school when in fact all you're doing is verifying what I said in the first post. The high voltage lines still have HIGH current, it's not like you can go play with it.

did you miss the part about it takes 100 Milli amps to stop the human heart?
I don't disagree with any of the MATH in your post. You're preaching to the choir here. THE reason higher voltage is used is to eliminate line losses period. The current is still enough to kill you. A transformer tends to resist a change in current. Where in your post did you prove this wrong? Where in my post did I say that the high voltage WAS NOT used to help maximize line loss? and power loss. I dont disagree with you.... if you use a higher voltage, You have the ability to do more WORK ( Watts ) with less current as is obvious by W = I*E but that by no means makes a power line low current. 240 amps is not low. go back and read my first post and do that search :p

Now what's wrong with that? Tire smoke smells good.

Larry

You neglected to mention which is better for his 'Vette...higher current, higher voltage or both...

Get back on the subject or start another thread in the lounge.

It is you who attempted to take ME to school!
You flat out tell me I'm wrong than attempt to back it up with a lesson on Ohms law!
This is what I said:

And your Reply:

Why don't you explain to me again why my initial post is incorrect.: You tried and you CANT!
Nowhere in your rant did you mention POWER, No where at all!
You tell us, in detail how transformers work, and give a whole lesson on ohms law that does ABSOULTELY NOTHING to refute my original post. You insist that if voltage goes up current must also. Duh. Since I was discussing power line transfer, and you failed to mention power at all, there seems to be no indication from your post that you were even aware of this. Your reply certainly did nothing to disprove my point. Now you try to say you agree and I am only validating your point?

I Never said you could "play with it". As a matter of fact I said "relativley" low current. Do a search on "relative". The current is lower RELATIVE to what is being delivered to the low voltage loads. Get it now? This is the point that set you off. You only solved part of the equation. You ignored POWER. You only considered voltage and current. Your bad.

FYI:
I can produce enough current with 120V (or less) to kill you. It only matters if your body resistance is low enough. SAFETY is not why it is stepped down, It is stepped down to recover the current that you need for your home. It is stepped down because your house can't use 24,000 volts.

This is what you said:

Please quote where I agree/repeated what you said about the insulators.
As I said, those insulators are used to prevent arc over from high VOLTAGE not high CURRENT. I can surely send 1000 amps (or more) down a wire at low voltage (lets say 12 volts) and I wont need a mica insulator. Wood would work fine. Even at 1000 amps. 12 volts will NEVER jump an arc through the air.

Lets see now:
1) Explain what was wrong with my first post.
2) Explain why wood can't be used for high current, (not high voltage) insulation.
3) Quote where I agree/repeated what you said about the insulators.
4) Explain why SAFETY is the reason why voltage is stepped down.
You tried to come off like some know it all and you got SPANKED!
You said I was wrong, now back it up or shut up!
Let the backpedaling begin!