2V vs 4V

So horsepower tv says that 2V heads are better than 4V on the street, and that edelbrock clever heads on a windsor produce more HP and torque than a cleveland. Very interesting to say the least. So what do the real experts think about this?

So horsepower tv says that 2V heads are better than 4V on the street, and that edelbrock clever heads on a windsor produce more HP and torque than a cleveland. Very interesting to say the least. So what do the real experts think about this?

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2v heads are better for the street than 4v because you get velocity at lower rpm with the smaller port size which provides instant torque at street rpms. Now at 5000 and above move over 2vs, the 4vs come alive at about this rpm. For hot street performance my motor man who helps kevin harvics engine program takes 2v castings and adds 4v valves cut down to I believe 2.08 intake and just under sized on the intake and wow does it respond well! As far as new edelbrocks 45 year newer head technology will run circles around the older stuff.

So horsepower tv says that 2V heads are better than 4V on the street, and that edelbrock clever heads on a windsor produce more HP and torque than a cleveland. Very interesting to say the least. So what do the real experts think about this?

Click to expand...

2v heads are better for the street than 4v because you get velocity at lower rpm with the smaller port size which provides instant torque at street rpms. Now at 5000 and above move over 2vs, the 4vs come alive at about this rpm. For hot street performance my motor man who helps kevin harvics engine program takes 2v castings and adds 4v valves cut down to I believe 2.08 intake and just under sized on the intake and wow does it respond well! As far as new edelbrocks 45 year newer head technology will run circles around the older stuff.

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Watched it...I call bogus....you cant use the same cam profile or carb set up for 2v and 4v heads...You need a more agressive cam for the 4v heads...They will handle more air intake and gas than any 2v heads...fact...CFM rating on 4v heads need alot more...You cant just change the heads and say...Ok!...And they dont mention what manifold they used on the 4v motor...If they just slapped the 2v one on top...It would have issues making good horse power....I didnt like it....they should of built them separately....And put a cam profile in the 4v motor that would take advantage of the big heads.

Looks like they used the same trick flow track heat manifold.

Warning: This is my standard statement to the 2v v 4v debate:

If the statement you provide is so true, why would Ford go to all the expense of making this exotic 4V head when they could have just slapped a carburetor and manifold on the 2V?

Are there some advantages to 2v heads over 4v heads? Sure, just like there are advantages to a 2v carb over a 4v, or a 2.75 rear end to a 3.75.

Decide on the end product, and work your way backwards. And if someone tells you a 4V doesn't have low end HP or torque, find someone here who can give you a little test drive. And then let us know what you think.

They said the Cleveland was being built for the street, and then they put a tall single plane intake on it and use the same manifold on both heads. And, talking about the heads, they used open chamber 4V heads, which are a compromise dictated by emissions, and not what Ford originally designed.

Depends on the RPM's your wanting to turn to while gettin up to the legal speed limit. Me, I love merging! 4V

Just want to chime in and say that I'm happy this discussion is continuing after over 40 years of debate!

Just want to chime in and say that I'm happy this discussion is continuing after over 40 years of debate!

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LOL...True...same with 351 vs 351..hehehe

..they used open chamber 4V heads, which are a compromise dictated by emissions, and not what Ford originally designed.

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Warning...soapbox.

Until this century, and as a Detroit teenager with inside connection, I don't think any of the automotive mfr's had a handle on emissions. The people in Washington DC and the People's Republic of California imposed impossible standards with impossible deadlines. And everyone in this country paid the price in more expensive cars that burned more fuel than they had to...in the name of clean emissions. In some cases, perfectly good cars were scrapped because of unavailable or overly expensive "emission" parts. In others, because California required Non OEM retrofitting kits, cars had increased occurrence of overheating, and all the damage that came with it.

The only saving grace was the catalytic converter...until you examine the output. Two major components. CO2 and water vapor. Everyone realizes CO2 is a greenhouse gas. But very few are told, and the EPA and DOE refuse to identify, water vapor as an even more damaging greenhouse gas. In fact, 60% of the known greenhouse gas is water vapor. 1lb of water vapor does 10 times more "greenhouse" damage than 1lb of CO2. CO2 is about .039%...yes .039% of our atmosphere.

So. That being said, never mention emissions again.

..they used open chamber 4V heads, which are a compromise dictated by emissions, and not what Ford originally designed.

Click to expand...

Warning...soapbox.

Until this century, and as a Detroit teenager with inside connection, I don't think any of the automotive mfr's had a handle on emissions. The people in Washington DC and the People's Republic of California imposed impossible standards with impossible deadlines. And everyone in this country paid the price in more expensive cars that burned more fuel than they had to...in the name of clean emissions. In some cases, perfectly good cars were scrapped because of unavailable or overly expensive "emission" parts. In others, because California required Non OEM retrofitting kits, cars had increased occurrence of overheating, and all the damage that came with it.

The only saving grace was the catalytic converter...until you examine the output. Two major components. CO2 and water vapor. Everyone realizes CO2 is a greenhouse gas. But very few are told, and the EPA and DOE refuse to identify, water vapor as an even more damaging greenhouse gas. In fact, 60% of the known greenhouse gas is water vapor. 1lb of water vapor does 10 times more "greenhouse" damage than 1lb of CO2. CO2 is about .039%...yes .039% of our atmosphere.

So. That being said, never mention emissions again.

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Yes Sir...

lol

I agree with hyena, the 4V should have had more fuel and bigger exhaust to be a fair comparison

Even keeping the same cam, if they had a different exhaust and more fuel, would it have made more power? By saying more fuel, do you mean more carb or should they have re-jetted?

Even keeping the same cam, if they had a different exhaust and more fuel, would it have made more power? By saying more fuel, do you mean more carb or should they have re-jetted?

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Well....A motor can only suck so much fuel and air...due too size of valves,head and carb....the bigger the valves and head..the more fuel and air it can handle..and more agressive cam profile....and yes..they should of rejetted it much bigger..or just a bigger carb....sence the bigger head could handle more air and fuel than the 2v's.

See if you put too big of a carb for a motor...It will lean out..Not flood out....If you put too small of a carb on a motor..it will flood out...Its cause the motor will suck as much fuel and air it can handle....It all counts on the carb combo too keep it equal...carb makes sure the fuel stays adomized....So a carb too small for your motor will pull too much fuel and not enough air too mix....Fuel turns too rain drops and floods your motor cause not enough air mix.....A bigger carb will pull too much air and not enough fuel on smaller heads and will lean out....So that 4v is almost being flooded out in a way...too small of a carb to realy get its full preformance...motor is nothing more than a air pump..lol...restrict what it can do..and you will see a big loss in preformance.

a 4v head is able to handle up too 800 too 1000 hp built right...It can handle more hp than the block can handle....there is no reason with the right cam profile "even with that carb" should of pulled more hp....i think its cause of the wrong set up...wrong cam profile...wrong carb...even wrong pistons.

http://www.7173mustangs.com/thread-the-amazing-351c-4v <~~a good thread and idea of what a cleveland can do...its suposta be a message from the pantara club nat president too bill who designed the cleveland..and why.....if you notice with a 6.00 lift...same lift as hemi's and 427's...its making just as much or more power...with right carb combo and 4v heads and cam...you should get too about 550 hp too 600 hp out of a cleveland...the motor is over designed and well made...it has years and years of fords race tech stuffed in it...its 20 years ahead of the 302 or 351w..old designs

Btw...One more issue i got with the build they did with the head swap....4v heads close or open? you need to pick the right pistons..open mite need a pop up piston to boost compression...closed dont...wrong pistons would make the motor drop power in open chambered heads....opens will get alot of power..but they need to be set up right...like i said..you cant just swap heads and keep everything the same....I see lots of issues with doing that and not changing the cam...the carb...the pistons even...the manifold...You cant use the same manifold for a 2v and 4v...i guess i could go on and on and beat this dog to death hehehe

No, I'm starting to understand. It looks as if they needed to do a completely different build for the 4v Cleveland. I guess a good build would be to build up the 4v and the 2v to their potential and see how they differ.

They did prove one thing. Look again at the power and torque curves. The 2v builds power on the bottom end up to 4500 rpm. No matter what you do to the 4v combination it will not improve the low rpm power. The 4v combination will make more power but it will be higher in the rpm range where that head works best. Both combinations are compromizes, the 2v head set-up needed a performer air gap to make it's best low rpm power. If they had maximized both combinations to take advantage of the strengths the 4v would not touch the 2v under 4500 and the 2v would not touch the 4v above 4500 rpm.

Now one final question... what makes a car move horsepower or torque?

They did prove one thing. Look again at the power and torque curves. The 2v builds power on the bottom end up to 4500 rpm. No matter what you do to the 4v combination it will not improve the low rpm power. The 4v combination will make more power but it will be higher in the rpm range where that head works best. Both combinations are compromizes, the 2v head set-up needed a performer air gap to make it's best low rpm power. If they had maximized both combinations to take advantage of the strengths the 4v would not touch the 2v under 4500 and the 2v would not touch the 4v above 4500 rpm.

Now one final question... what makes a car move horsepower or torque?

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I have to dissagree a bit...its unfair...they had the block decked and 2v heads milled to get more compression and got pistons with valve recesses in the pistons...then they slapped on a pair of 4v open chambered heads ...so the poor 4v heads are getting less compression...than the 2v heads...So of cource the horse power wont ever be correct..Unless you build the 4v right...right pop up dome pistons so they would have the same compression....right everything...right cam....I have to call it failed test too me..Its unfair....Why shouldnt the 4v heads get the same compression? i would not put a dollar on there facts at this momment....I will state the test proved one thing...The 4v heads with less compression and wrong cam profile.....made just as much HP on the top end and more than the 2v heads with more compression and the right cam profile.

Then...they dont state if they change the 2v manifold too a 4v manifold...which would cause issues...it would work..but cause some loss...i dont think there is a universal 2v...4v..manifold is there?

I think you missed my point. If BOTH combinations were built to take advantage of their strengths, the 2v would win at under 4500 rpm and the 4v would win at above 4500 rpm.

The valve releif in the pistons have nothing to do with it. Comparing open chamber to open chamber is comparing apples to apples as they have the same sized chambers. Cutting the deck surface of a head to true the surface has minimal effect on compression and is best practice when rebuilding a set of heads.