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engine 351 cleveland
#1
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Hi there, my name is Ted from PEI, Canada, while there is lots of snow on the ground, I decided to haul the engine out and detail the bay and the engine. The engine is a stock Huh351 C a 2V carb, with 2V heads, I am adding a 600 Holley, Edelbrock Manifold, cam and lifters, headers as well as HEI ignition. to increase power a bit. My question is, I have access to set of "big" Cobra jet heads, however I have been told to keep the 2V heads since the car will be be solely used on the street and the big heads will make it sluggish on the low end, which is where I want the power? any ideas?
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#2
I'm probably in the minority here but I say keep the 2v heads. They have better flow velocities at moderate engine RPM.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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#3
droptop73;58531 Wrote:I'm probably in the minority here but I say keep the 2v heads. They have better flow velocities at moderate engine RPM.


shellbuyer;58536 Wrote:
droptop73;58531 Wrote:I'm probably in the minority here but I say keep the 2v heads. They have better flow velocities at moderate engine RPM.
Thank you...

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#4
shellbuyer;58529 Wrote:Hi there, my name is Ted from PEI, Canada, while there is lots of snow on the ground, I decided to haul the engine out and detail the bay and the engine. The engine is a stock Huh351 C a 2V carb, with 2V heads, I am adding a 600 Holley, Edelbrock Manifold, cam and lifters, headers as well as HEI ignition. to increase power a bit. My question is, I have access to set of "big" Cobra jet heads, however I have been told to keep the 2V heads since the car will be be solely used on the street and the big heads will make it sluggish on the low end, which is where I want the power? any ideas?

Counts how much power you want...There are people paying 2000 plus dollars per head too have the flow that stock 4v cobrajet heads have...Huge 2.19 vavles...But if you want a truck lugging style of power...Not the heads for you!!..lol

Thou have had no issue lugging my mustang around with its big heads..But if your just going 600 cfm holley..You proably dont need it....Once you start getting over 300 horse power thou and a holley 750...You will need to look into some better heads...They just cant flow like the cobra heads..Which can flow up too 900 horse power if you want to get nuts with them...lol...But if you want your power curve too be in 1,500ish RPM too 5,000...They perfict for you....Cobra jet heads like too run 2,500 up too 6,500 all the way too 7,000 RPM if built right...apples and oranges..And corbajet heads do work good on the street..You just need to know where the power is and how to use them.
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#5
+1 on hyena429's post. If you have the 2v and want a cruiser with "highway" gears use what you have. I will however, debate those who say 4V heads don't work well on the street. You just need to select the parts carefully, be willing to run a somewhat numerically higher gear, and wind it up a bit more. Chuck
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#6
A while back I had asked on this site why someone might have taken the 4V heads off my 71 Mach 1 M Code engine and put 2V heads, edelbrock 2750 intake and the Autolite 4300D carb back on. The 4V intake was in the trunk when I bought the car. Posters explained the previous owner may have did it for drivability. I recently was able to get ahold of the previous owner and asked him if he still had the 4V heads. He explained he had "traded" the 4V heads for the 2V heads several years ago because he lives in an urban area of stop and go and needed the power at low RPM's for city driving. He explained the 2V heads were much more "friendly" for the driving he did but the 4V's were better for the few times he did get out on a stretch of road and "opened it up". I've since removed the Autolite 4300D and put it on a shelve with the 4V intake, I replaced it with an edelbrock 650cm thunder series carb, the 41 year old Autolite required to much attention, "even after paying 380 bucks to have it rebuilt". It runs and starts much better with the Edelbrock over the Autolite...guess they've made improvements in the last 41 years in carbs.Wink

The guy I bought the car from told me the 4V intake and the Autolite are original to the engine, from the data on the items can anyone advice if that's "consistent" with a 71 M code 351 Cleveland, car manufactured Dec 70?

I know you guys like challengesBig Grin

Intake stamped - D1ZE-9425-BB
Carb- Autolite tag - D10F EA AOL 11

   
.jpg   Intake.jpg (Size: 117.73 KB / Downloads: 140)
.jpg   Carb.jpg (Size: 54.8 KB / Downloads: 138)

Jim

M code 71 Mach 1, 351 4V Cleveland, Ram Air (not factory), C6 Trans, 3.5 rear
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#7
This won't be any help....

I don't know what the definition of "low end" is, as in the car will be much better on the "low end".

Does that mean it will be faster from 0-30? 0-40? 0-50?

I have never been in a 351C with 4V carb, 4V intake and 2V heads. I hear a lot of talk. But I don't see any numbers such as actual torque, actual HP, actual drag times. More than likely, the "science" is right.

But, when I floor my car on the freeway, I don't think I am on the low end for very long. When I run(try to run) my car up to 5000 RPM in first gear, I don't think I am on the low end.

When my current 302 4V 73 Convertible reaches 4500 RPM and stops there, that is crap. Just cant get past that point...no fuel/air IMHO

On my next motor, I am not taking that chances. I spend too much time fretting over every torqued nut, journal, piston ring, do I have the right shade of BLUE, etc. I am not going to spend all that time and have my motor wimp out on me.

351 4V Quench heads. Anyone out there regretting they choose 351 4V Quench heads instead of 351 2V's? Anyone?

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#8
Jim and Jutta;58660 Wrote:A while back I had asked on this site why someone might have taken the 4V heads off my 71 Mach 1 M Code engine and put 2V heads, edelbrock 2750 intake and the Autolite 4300D carb back on. The 4V intake was in the trunk when I bought the car. Posters explained the previous owner may have did it for drivability. I recently was able to get ahold of the previous owner and asked him if he still had the 4V heads. He explained he had "traded" the 4V heads for the 2V heads several years ago because he lives in an urban area of stop and go and needed the power at low RPM's for city driving. He explained the 2V heads were much more "friendly" for the driving he did but the 4V's were better for the few times he did get out on a stretch of road and "opened it up". I've since removed the Autolite 4300D and put it on a shelve with the 4V intake, I replaced it with an edelbrock 650cm thunder series carb, the 41 year old Autolite required to much attention, "even after paying 380 bucks to have it rebuilt". It runs and starts much better with the Edelbrock over the Autolite...guess they've made improvements in the last 41 years in carbs.Wink

The guy I bought the car from told me the 4V intake and the Autolite are original to the engine, from the data on the items can anyone advice if that's "consistent" with a 71 M code 351 Cleveland, car manufactured Dec 70?

I know you guys like challengesBig Grin

Intake stamped - D1ZE-9425-BB
Carb- Autolite tag - D10F EA AOL 11

Jim, there will be date codes on the intake
On the carb tag the O L 11
DEC 11th of 1970 I think that is correct.
Check with Chuck , C9ZX he will know the date info
Don

Ohio Mustang Supply
440-949-2556

[Image: oms_sig_banner.jpg]
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#9
c9zx;58657 Wrote:+1 on hyena429's post. If you have the 2v and want a cruiser with "highway" gears use what you have. I will however, debate those who say 4V heads don't work well on the street. You just need to select the parts carefully, be willing to run a somewhat numerically higher gear, and wind it up a bit more. Chuck

- And a 351C w/4bbl heads, a Torker, nice sized double-pumper and high-lift cam sounds really good as it powers through a 4" size open collector from 5500-7800! Big Grin

Ray

1971 Boss 351  
1972 Q code 4 speed convertible 
1971 Mustang Sportsroof  351-2V FMX 
1973 Mach 1 (parts car)
  Reply
#10
OMS;58668 Wrote:
Jim and Jutta;58660 Wrote:A while back I had asked on this site why someone might have taken the 4V heads off my 71 Mach 1 M Code engine and put 2V heads, edelbrock 2750 intake and the Autolite 4300D carb back on. The 4V intake was in the trunk when I bought the car. Posters explained the previous owner may have did it for drivability. I recently was able to get ahold of the previous owner and asked him if he still had the 4V heads. He explained he had "traded" the 4V heads for the 2V heads several years ago because he lives in an urban area of stop and go and needed the power at low RPM's for city driving. He explained the 2V heads were much more "friendly" for the driving he did but the 4V's were better for the few times he did get out on a stretch of road and "opened it up". I've since removed the Autolite 4300D and put it on a shelve with the 4V intake, I replaced it with an edelbrock 650cm thunder series carb, the 41 year old Autolite required to much attention, "even after paying 380 bucks to have it rebuilt". It runs and starts much better with the Edelbrock over the Autolite...guess they've made improvements in the last 41 years in carbs.Wink

The guy I bought the car from told me the 4V intake and the Autolite are original to the engine, from the data on the items can anyone advice if that's "consistent" with a 71 M code 351 Cleveland, car manufactured Dec 70?

I know you guys like challengesBig Grin

Intake stamped - D1ZE-9425-BB
Carb- Autolite tag - D10F EA AOL 11

Jim, there will be date codes on the intake
On the carb tag the O L 11
DEC 11th of 1970 I think that is correct.
Check with Chuck , C9ZX he will know the date info
Don
Don is right on carb date code. It looks like part of the date code on the intake is visible as 2Dxx. If so, that decodes as 1972, April, xx. Chuck
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