More 2v / 4v questions
#1
My project is on it's way so the details may change, but I am supposed to be getting:

351c, bored 40 over
4v heads
flat top pistons, 40 over
Meuling cam
Roller rockers

Stock 351c 4v's were 300hp, according to some quick research.
My goal is 400hp, from some bolt ons:
Headers
carb and intake
MSD ignition
cam, if the Meuling isn't good enough

I don't want the 400hp to come at the expense of torque. 400hp is a "cool factor" number I chose based on the thought that I should be able to bolt on enough to get up there.

I had it recommended that I swap out to 2v heads. It was said that 4v throughout would sacrifice torque for power at higher rpms.

I'm sure that either way I go it will make for a great cruiser. But I want more torque than top end speed. I will be getting rid of the FMX and getting a T5. I want to be able to downshift and hammer it and worry about spinning the wheels.

Will 4v throughout still accomplish this?
Is it best to swap the 4v heads for 2v like was already recommended to me?
Zac





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#2
351Clevelands were a thin walled casting
Most motor guys will say .30 over is the maximum over-bore.


Your post stating the 300 HP would have been for a 4 V closed chamber head.

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#3
What you have to realize is that the 2v head is not horrible. It has 2.05 intake valves and 1.65 exhaust valves! Thats bigger then Chevys "Famed" 2.02 Heads and the ports are definetly larger and much better flowing. So the worst Cleveland head is still way better then anything Chevy ever produced, and they can get 400+ HP, out of a Small block Chevy. So 400HP is quite easy to achieve with a 351 Cleveland and 2v heads. The 4v head is so much larger in port and valve size. Then the 2v, that it does give up some on the bottom end. But if you size the cam to your combination, and get a cam that works from 2500 to 7000rpm. With the T5 you will be able to pick the gear to match the power band. It s sorta like the heads do the breathing but the cam is the "Brain" and tells them when to breathe! So either way you can make it run, with 2v or 4v heads. Go to compcams and download there camquest and put in all your specs, and it will give you a couple choices for the cam and you can even click on the Dyno results at the bottom of the page and it will tell you what kind of HP and Torque to expect. Great tool! (be careful with the T5, unless it is a world class, its torque capacity is 300 to 350 ft. pounds of torque and the Cleveland with 400hp will easily produce similar torque numbers). Hope this helps JTS 71 Mach1
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#4
(07-30-2012, 09:46 PM)ohiomustang Wrote: 351Clevelands were a thin walled casting
Most motor guys will say .30 over is the maximum over-bore.


Your post stating the 300 HP would have been for a 4 V closed chamber head.

From this side view can you guys tell if this is a Cleveland?

[img][Image: Pic11.jpg][/img]

Isn't that the upper radiator hose/thmostat position at the upper left of the screen?
Zac
(07-30-2012, 09:46 PM)ohiomustang Wrote: 351Clevelands were a thin walled casting
Most motor guys will say .30 over is the maximum over-bore.


Your post stating the 300 HP would have been for a 4 V closed chamber head.

I just looked at some pics on Google and it sure looks like a Cleveland to me.
That being said, what do I have to watch out for since I'm inheriting a .40 over setup?
Zac
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#5
Yes it is a Cleveland

Since you are inheriting it, if you are getting the 40 over pistons too
Use it, I know a couple of guys running 40 over and they are OK
It can over heat and crack.
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#6
My cleveland is bored 40 over and it has been that way for the last 3 or 4 years and has close to 7500 miles on it. I am running the stock rad and never had any problems with over heating or anything. Motor shop that built my motor estimated it at 400 hp. Runs great and is very streetable and fun. I wouldnt worry about the 40 over, but wouldnt want to go beyond that too much!!
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#7
(07-31-2012, 09:23 AM)turtle5353 Wrote: My cleveland is bored 40 over and it has been that way for the last 3 or 4 years and has close to 7500 miles on it. I am running the stock rad and never had any problems with over heating or anything. Motor shop that built my motor estimated it at 400 hp. Runs great and is very streetable and fun. I wouldnt worry about the 40 over, but wouldnt want to go beyond that too much!!

Thanks for seconding what Ohio said. I had already planned on an electric fan so I guess I will keep with that thought so I can have that peace of mind.

Did you go the 4 barrel carb to 2V heads route?
Are there any identifying features of these heads, other than that they are 4V heads?

[img][Image: Pic13.jpg][/img]

Any way to tell if they are closed chamber heads?
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#8
4 V heads will have a 4 cast into the upper front corner

Send a pic of the other side or casting numbers to idenitfy them
D0??-??

D1??-??

D2??-??

D3??-??
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#9
Yeah i am running the 2v heads with an edelbrock rpm manifold and holley 750dp. the heads were shaved, heavily ported, and milled for screw in studs and running 1.73 harland sharp roller rockers. Its been working great for me.
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#10

I agree with OHIO MUSTANG.

If its 40 thousandths Id toss the whole block and not risk putting it together only to have to re-lick your wounds of not listening to many Ford Builders who tell the story of the thin walled casting.

get yourself a stock block from 1970 -1974.
Strip it down and take it to the machine shop.

I just went through this nigh mare and I thought at first tha my head gaskets were the reason my engine kept overheating.
I replaced everything under the sun trying to cool it down.
New 650 dollar 4 core Brass radiater,
New water pump, The correct (NOS) 351 Cleveland thermostat..(very expensive). New fan, new head gaskets.

Dont risk the costs of all this expensive parts for your rebuild only to be the victom of an internal crack deep down inside the waterjackets of your block and have the hairline crack pressurize your entire cooling system and blow out your heater core....(yes thats another long job fixing)

Just my two cents.Biggrin...Good luck.....ya better think really hard!!

If you have deep pockets they now make an all aluminum (titus 351 Cleveland) engine good for up to 3000 horsepower..Its about $4,900.00
That sucka can be bored to the hilt with the huge steel sleeves in it.
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