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Dyno 351C 2v vs 4v Heads


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You can make your own conclusions on the two options the Dyno doesn't lie!

 

I am definitely a fan of the 4v heads (wish I had a pair) but this will give 2v ppl something to cheer about... after all who winds up their C past 5K other than pro street drag cars.

 

http://www.powerblocktv.com/two-minute-tech/2min-239/head-comparison-351-cleveland

 

Regards

Paul

73 Grande

351C 2v

Now 4v Carb/Cam/headers/T5

 

Gasoline is for washing parts.

Alcohol is for drinking.

Nitomethane is for racing!

 

 

Work in Progress photos here:

Last Update: 4/23/16

 

http://s1270.photobucket.com/user/therocket366/library/?sort=3&page=1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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I wish they made a closed chamber 2v.

If you don't have time to do it right the first time, you sure as Hell don't have time to do it right the second time.

 

Dutch uncle

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I wish they made a closed chamber 2v.

 

Aren't the aussie cylinder heads closed chamber?

351w - Ford racing GT40X 178 cc aluminum heads - Ford racing(crane) 1.7 roller rockers - Comp Cams 280H magnum cam .544" / .544" lift - ARP hardware - hedman longtubes - magnaflow exhaust with X pipe - Duraspark - MSD digital 6al box - MSD TFI coil - optima red top battery - tuff stuff 140 amp alternator - weiand stealth intake  - edelbrock 1406 600 carb  - march pullies and brackets - Be cool fan controller - derale electric fan - FMX trans - motive 4.11 gears - traction lok - lakewood traction bars.                                            

 

 

 

 

 

 

 

 

 

 

 

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That test, was BS, to be nice... The 4V heads need way more cam then they put in that build. They also short changed it on RPM and static compression ratio.

1973 Mach 1 Q code 351 4V, 9A paint, standard interior, 3.50 rear, C6 trans.

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That test, was BS, to be nice... The 4V heads need way more cam then they put in that build. They also short changed it on RPM and static compression ratio.

 

+1

Too many variables here in my opinion to make this an accurate test, They mentioned that the intake, carb and headers remained the same with only a head change. Port sizes are different so I am thinking that the flow rate was restricted on the 4v heads and they weren't allowed to breath freely. I would have expected to have seen more HP produced in the upper RPM range along with more torque. The 2v heads are good heads for street use and probably make more power initially however by 5500 rpm the 4v's should have shown much more power gains than this test showed. Were the 4v heads getting enough fuel?

-john

(jbojo)

351C 4V cc heads, 10.5 : 1 CR, 290 Herbert cam, Flat top forged pistons, forged connecting rods, Atomic efi,

C6 with Gear Vendor overdrive, 3.89 Tru Trac, Hooker Super Comp with 2 1/2" Pypes Exhaust.        

 

Some Mod pictures can be seen at: [button=http://www.7173mustangs.com/forum-garage?filterxt_uid=2026]Bojo's Garage[/button]

 

 

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i remember watching this test (saved on my DVR) and referenced to it as i selected my top end rebuild components last year. used these 2 episodes more as a reference in what NOT to do for my 4V build.

 

1. Single planes live at 6000-7000-8000 RPM on a small block (302 - 351)... but will do well as low as 4000 on a Big Block or Stroker motor.

LESSON: DON'T USE A SINGLE PLANE ON A 4V UNLESS YOU STROKE THE MOTOR OR PEAK YOUR POWER BAND ABOVE 6500 RPM.

 

2. The fast acting cam with 224 dur and moderate lift of 566 is a good street cam if mated to a dual plane intake.

LESSON: IF YOU HAVE DUAL PLANE, OR AS IN MY CASE, A FTY SPREADBORE INTAKE, AND IF YOU ONLY PLAN TO OPERATE BELOW 6500 RPM, USE IT. DON'T MATCH A 4V TO SINGLE PLANE AND EXPECT TO OPERATE DECENTLY BELOW 5500 RPM. THE 4V IS MADE TO ROCK ABOVE 6500 WITH A SINGLE PLANE AND BELOW 6500 WITH A DUAL PLANE. THE 2V'S SMALLER RUNNERS WILL FLOW BETTER BELOW 5500RPM SINCE VELOCITY IS HIGHER DOWN LOW.

 

3. The show's Comp cam peaked at 5500 rpm... too low on a 4V?? when i talked to Comp tech for my build, they kept trying to sell me on a 112 LSA. I wanted 106-108 for my 4V. so, i just avoid Comp Cams for now. many variables could be causing the problem, fuel, air, cam... if they moved the CAM timing to 109, 108, 107, 106... I think they would start peaking at 6500-7000. at that point, the 4V with single plane will scream as it finds its sweet spot up high.

LESSON: COMP CAMS ARE NOT THE ONLY GAME IN TOWN. 110-112 LSA IS NOT MANDATORY. 109 LSA STILL HAS GOOD VACUUM. SEEK 220-230 DURATION AND 550-600+ LIFT IF POSSIBLE IN A STREET 4V APPLICATION.. I WENT WITH CAM RESEARCH, WHO SPEC'D A CAM BASED ON MY RPM RANGE, MY COMPONENTS, DRIVING STYLE, GOAL TO HAVE A MOTOR LAST 100,000 MILES...

 

4. the 2V will shine at 2000-4000. if the Cam was peaking at 5500 rpm, this will magnify the 2V performance parameters down low..

LESSON: NEVER UNDERESTIMATE THE 2V. IT'S GOOD ESPECIALLY IF YOU FOCUS ON TORQUE BELOW 5500 RPM. THE 2V IS STOPLIGHT TO STOPLIGHT BEAST. THE 2V MIGHT RUN OUT OF AIR ABOVE 5500 RPM.

 

above is pure speculative babble on my part because i'm not an expert or professional... don't listen to me...

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I would not own a 2BL plain and simple.

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I think it was cool episode to show the Clevelands but not fair at all. Having built a good running 2v motor with around 425HP It was fun and it did die out around 5700-6000rpm. I have a built 408 stroker now with aluminum AFD heads that is just unreal! Even low end torque is a monster and the 2v motor doesn't even compare to it in anyway. The afd heads are suppose to be the best of both the 2v and 4v design put together.

But for what my 2v motor was, it was a great strong running motor. Right up till the moment it ate a valve for lunch ;)

My new motor really comes alive from 3000rpm and up. Crazy how it pulls. But the idle to 3000 rpm is no slouch either. Cruising at 45mph I can jump on the throttle and have the tires instantly go up in smoke. Never had that pleasure with my 2v. But anyhow, ramble, ramble, ramble...... I think either motor can be built to what you want and need. Either way better than a CHEBY!!!

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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Dyno's most definitely lie all the time. The measured power output can be manipulated easily with the settings used.

 

Also, an engine like the 4V Cleveland that is built to maximize it's attributes will be very powerful across the board. My 393 4V's torque is 400+ ft lbs starting at 2000 rpm and smoothly moves up to over 550 at 5500. I can turn close to 8000 rpms and with my stud girdle everything stays stable. If I had built it with a compression ratio and a cam to max out at 6000 rpm, my engine would not perform optimally-the heads need everything else to match.

 

Powerblock isn't so bad, but they are sponsor driven and their show is about entertainment more than anything else. Creating controvery gets people talking about them


and my heads are unported-cut for clearance, but ports are untouched

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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Dyno's most definitely lie all the time. The measured power output can be manipulated easily with the settings used.

 

Also, an engine like the 4V Cleveland that is built to maximize it's attributes will be very powerful across the board. My 393 4V's torque is 400+ ft lbs starting at 2000 rpm and smoothly moves up to over 550 at 5500. I can turn close to 8000 rpms and with my stud girdle everything stays stable. If I had built it with a compression ratio and a cam to max out at 6000 rpm, my engine would not perform optimally-the heads need everything else to match.

 

Powerblock isn't so bad, but they are sponsor driven and their show is about entertainment more than anything else. Creating controvery gets people talking about them


and my heads are unported-cut for clearance, but ports are untouched

Can you provide some details on the build to get to the 550 lb/ft of torque? Like CR, intake, heads, and cam. Thanks, Chuck

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11.5 -1, Lunati Solid Roller with 641 lift, torquer intake, 850 holley DP, Performance distributor recurved for less advance 393 stroker internally balanced it's all in my bio page IIRC

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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I don't have a Dyno but I recently switched to closed chambered 4V heads from 2V heads and can tell you there is a very noticeable seat of the pants difference in performance and it's a good one. The only issue I encountered is that the engine is more cold natured with the 4V heads...put once warmed up, look out.

Jim

 

M code 71 Mach 1, 351 4V Cleveland, Ram Air (not factory), C6 Trans, 3.5 rear

 

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11.5 -1, Lunati Solid Roller with 641 lift, torquer intake, 850 holley DP, Performance distributor recurved for less advance 393 stroker internally balanced it's all in my bio page IIRC

 

Displacement is an amazing cure-all... nice build and sick hp/tq #s! must be a load of fun

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Yes, we had a destroked Cleveland (302) with quench 2 barrel heads.

 

I wish they made a closed chamber 2v.

 

Aren't the aussie cylinder heads closed chamber?

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I do agree the testing was not optimized for maximum performance in all fairness to the 4v combination. There is more to be had from that combination with better cam timing. We make more power than these guys did using the Ford "service" aluminum intake and 750 Holley. However for maximum performance on a stock stroke 351c the heads are just WAY too big and there are dead spots in the flow that kill maximum power potential. The 4v heads are good for a 400+ inch stroker and are not optimal for anything less.

 

The 351c powered race car I work (max overbore @ .085" and stroke +/- .015" per NHRA rules) on has the 4v ports filled an easy 25-30%, winds in excess of 8000 RPM and runs mid 9s at 140 MPH. No they are not 2v port configuration but are sized more like the 2v. The ports are raised as far as possible for best "line of sight" from the opening to the valve. I know the "Pence" guys that believe the 4v herads are flawless will disagree... performance doesn't lie. In real performance flow velocity is just as important as overall flow numbers. Afterall how do you think F1 cars and Pro Stock engines achieve over 100% volumetric efficiency from naturally aspirated engines?

[align=left]Jeff T.

 

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passengers. [/align]

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I agree with the test. It was a good test. (and we have been saying it here all along)

If you put a set of open chambered 4V heads on your 2v Cleveland and do nothing else.

If you keep the 2v intake and the 2v headers. (or exhaust manifolds)

If you don't adjust the timing and jets and maybe even the size of the carb.

If you don't match your cam to the build.

You will be disappointed.

Again, slap some 4v open chambered heads on a 2v engine with no other changes and you will be disappointed.

'Mike'

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

 

Pics of modifications included in: [button=http://www.7173mustangs.com/thread-1973-convertible--3335]My Garage[/button]

 

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rocket366,

 

A lot if interesting responses here! The first thing is, we all know that an engine is nothing more than a big air pump! Yep, It pulls air in and push air out. Just like a exhaust system, the biggest is not always the best for flow and efficiencies. I believe that the 351C 2V has always been known to be better for the street while the 4V was for the folks who wanted to run Wide open throttle. Here is some more interesting information from MPG Head Services.

 

351-302 Port Plates

 

Flat Tongue Port Plates

 

The plates fit between the intake manifold and exhaust manifold and cylinder head. Exhaust side: The MPG port plates' special tongue shape fills the floor area, allowing more airflow through a smaller port. Bolt on 20 HP and 20 ft lbs of torque and increase the velocity of airflow through your cylinder heads without reducing flow. There is no cutting or welding of the cylinder head and the plates attach using existing bolts. Made of high quality stamped steel and reusable.

 

Source: http://www.mpgheads.com/port_plates_a.php

 

MPG Port Plates

 

Based on our extensive study of airflow we have developed our MPG Port Plates. These port plates dramatically increase the amount of engine torque and horsepower.

 

Our studies have disproved many long-held assumptions regarding cylinder head porting. The shape of the port, not the size, determines the airflow through any port. Depending on their shape, smaller ports can flow more air than larger ones. This is why many of the new sophisticated race heads have significantly smaller ports than previous high-performance heads. When more air volume flows through a smaller cross-section, the air speed or velocity increases.

 

Airspeed in cylinder heads is important because it allows cam profiles with later intake valve closing points. Closing the intake valve later, in conjunction with very efficient (High-Velocity) intake ports, increases the volumetric efficiency (VE). This is commonly known as inertia supercharging. Using ports plates, and custom cam profiles can generate VE's in the 105% to 108% range.

 

Many people think that port plates restrict airflow, but actually port plates allow more air volume to flow through a smaller port. Additionally, they do not require machine work to install.

 

351C / Boss 302

Intake: On the street, or where midrange torque is important, the Cleveland ports are not effective. At midrange air velocity slows and the vacuum signals pulsing through the ports become confused because of the volume. Due to the slow air speed, fuel drops out of suspension, mixture distribution becomes a lottery, and throttle response is poor. The Cleveland heads need smaller ports, exactly what MPG Head Service delivers with our port plates. Our port plates force airflow into the naturally higher velocity section of the port and produce beneficial effects on throttle response and mixture distribution.

 

Exhaust: When the exhaust valve opens on a Cleveland or Boss 4-valve engine, the expanding airflow path wants to follow the roof of the port. However, the floor of the port falls off dramatically at the header/exhaust manifold junction, causing the column of air to expand. Whenever a column of air expands, it stops flowing or stalls.

 

The port plates raise the exhaust port floor approximately 1.5 inches. When the engine RPM is low, the column of exhaust gas wants to reenter the exhaust port (because of 14.7 inches of atmospheric pressure in the exhaust system). This phenomenon is known as reversion and it hurts low RPM torque by diluting the quality of intake mixture in the cylinder. The port plate creates a wall that when the air column tries to turn and reenter the port. The air column strikes the plate and stays captured in the header pipe, where it belongs.

 

Source: http://www.mpgheads.com/port_plates.php

 

 

mustang7173

Thanks,

mustang7173 🇺🇸

"Courage is being scared to death but saddling up anyway" -- John Wayne

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Port Plates... Way Cool that is new to me!

 

Photo...

 

http://www.mpgheads.com/port_plates_a.php

 

I've been out of the hot rod game for some time due to the local drag strip closing

and the smog requirements here in CA. Now pre 76 cars = smog exempt.

 

What I remember is in the late 70s when i had a 69 302 Mustang I was hankerin to

have a 351c 4v engine but I didn't have the coin.

 

My 351 2v engine has a boatload of torque and wants to spin the 10 inch wide tires so easily

I have to be careful.

 

My 73 is bare bones under the hood and the engine only has the necessary stuff Carb, Cam, Intake, and headers no smog no extra crap or hoses.

73 Grande

351C 2v

Now 4v Carb/Cam/headers/T5

 

Gasoline is for washing parts.

Alcohol is for drinking.

Nitomethane is for racing!

 

 

Work in Progress photos here:

Last Update: 4/23/16

 

http://s1270.photobucket.com/user/therocket366/library/?sort=3&page=1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Well technically it doesn't pull air in. ;) It lowers the air pressure below outside pressure and the result is air is pushed in. :)

'Mike'

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

 

Pics of modifications included in: [button=http://www.7173mustangs.com/thread-1973-convertible--3335]My Garage[/button]

 

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i decided to sell my MPG port plates... $45 (50% off reg price) + shipping. if anyone wants them, PM me. i can't seem to seal them correctly with my Sanderson headers, due to their raised flange design, but if you have stock exhaust manifolds or Hooker headers, they should work just fine..

 

FYI, my near-stock O/C 4V 351C (280HP/286TQ REAR WHEELS) is making #s at the rear wheels, similar to modern Mach 1s with all motor 4.6

 

http://www.dynoperformance.com/article_details.php?article_id=27

 

and our 351 4Vs seem to be as strong as or slightly stronger than our fellow 1971 429 Big Block brethren (370HP fty rating = 255HP rear)...

 

http://www.429mustangcougarinfo.50megs.com/new_page_39.htm

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Dave-

Thanks for the post, as I was about to ask about headers and the port plates. ( we are running Sanderson's, too)

I checked out the MPG website and didn't see any tech talk regarding whether the intake plates would still yield benefit if paired with a set of headers. Maybe I missed it? Thoughts?

[button=http://www.7173mustangs.com/thread-1973-mustang-convertible--19017]Visit My Garage[/button]

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Dave-

Thanks for the post, as I was about to ask about headers and the port plates. ( we are running Sanderson's, too)

I checked out the MPG website and didn't see any tech talk regarding whether the intake plates would still yield benefit if paired with a set of headers. Maybe I missed it? Thoughts?

 

Butch, welcome. i think MPG will say that they yield the most benefit and i'm sure they will be happy to sell you a set. :D

 

honestly, i felt a little more grunt down low when i had them in. but that is subjective. no hard #s. but a couple weeks ago, i dyno'd at 286 rwTQ (est 425-450 TQ-gross) without them and i'm ok with that since the orig fty spec was 286 tq-net at the flywheel. The ONLY 3 things I've done that deviates from STOCK that probably contributes to the huge increase, seem to be 030 overbore adding 6 cubic inches, slightly higher lift cam (0.030+) over stock (0.491-.505ish), and the sanderson shorties. everything else is bone stock or near stock.

 

the intake tongues & port plates are a "bolt on" solution to turn a 4V into a 2V or 3V more or less, but with a lot more velocity (pushing same amount of air but thru a smaller hole?) than a 2V.

 

i think people with LONG TUBE headers on a stock stroke 351C might benefit the most since long tubes seem to reduce the HP and TQ #s down low while raising the HP's up higher... the port plates might help to move the power band back down a little... stroker motors can forget about the port plates, they solved the TQ problem with displacement.

 

comparing my original Boss 351 exh manifolds (headers) to the Sanderson shorties, i don't see much difference in "packaging" (space used). The only real difference are the longer individual tubes and 3" collector vs the Boss's 2-1/4" collector. Standard 351C 4V had 2" collectors, as i recall. on street motors, i think larger collectors reduce TQ at lower RPM but helps HP at higher RPMs.

 

sorry for writing another book... ugh...

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I do not think it is fair, how can you use the same cam for the diff heads ? "Sure you can" but even Ford had to stick a "special" dual pattern cam in the 4v cleveland for good reason. 2v cleveland has more equal airflow potential on the intake and exhaust sides, a single-pattern cam is sufficient. When the airflow differs between the intake and exhaust," Like in a 4v cleveland" a dual-pattern cam needs to be used to balance flow through the engine. To be a fair test, they needed to switch to a dual pattern cam with the same lift. 4v cleveland will never flow quite right with a single pat cam.

 

And if i remmeber this build right, they used a single profile cam for both engines..I cannot find on there site the build part anymore..They use to have it all last year. Unless some one knocked them around for using the same cam on both heads ;)..lol

 

 

http://www.7173mustangs.com/thread-the-amazing-351c-4v <~~ from this classic tread..Cleveland 4v heads stock intake port was optimized for 0.600 inch valve lift.

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