Which type of 4V heads are this ?

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hassi01

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Hello,

My 4V Cleveland was an original 2V version. It has been modified by another owner. As I mentioned in a view days before I plan to stoke the block to 393 or 408 cui.

Due to the compression rate I have to know the type of my 4V heads because there are 4 differed versions and I don`t know what`s on my engine (but I know there are no BOSS heads)

• Standard 4V (61-64cc)

• Cobra Jet (74-77cc)

• High Output (74-77cc)

• Boss (64-67cc)

My question is how can I check the type of my 4V heads without dismounting them?

IMGP1778-1.jpg

 

Tnfastbk

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Hello,

My 4V Cleveland was an original 2V version. It has been modified by another owner. As I mentioned in a view days before I plan to stoke the block to 393 or 408 cui.

Due to the compression rate I have to know the type of my 4V heads because there are 4 differed versions and I don`t know what`s on my engine (but I know there are no BOSS heads)

• Standard 4V (61-64cc)

• Cobra Jet (74-77cc)

• High Output (74-77cc)

• Boss (64-67cc)

My question is how can I check the type of my 4V heads without dismounting them?

If you can find the casting number on them:

http://home.comcast.net/~jelerath/mustang/Specs/heads-fr.html

http://mustangtek.com/heads/Heads.html

 

Hemikiller

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Those are either the standard "M" code 70-71 closed chamber heads or the CJ open chambers due to the bolt down style rockers. The HO and Boss heads had adjustable rockers with studs and guideplates.

IIRC, the little dot next to the 4 may denote the type of chamber. I 'll have to look at my CC heads again.

 

Tnfastbk

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Those are either the standard "M" code 70-71 closed chamber heads or the CJ open chambers due to the bolt down style rockers. The HO and Boss heads had adjustable rockers with studs and guideplates.

IIRC, the little dot next to the 4 may denote the type of chamber. I 'll have to look at my CC heads again.
HK from my understanding and all that I can find on the dot beside the 4 that means you've got early 72 4v or earlier heads...ford retooled for the gas crunch after about february 72 and the dot dissappeared so odds are they are closed chamber heads.

 

david020278

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Hi Christian,

the casting number that you are looking for is on the under side of the heads (this is stupid). Look for the casting date code near the rocker arms. Dot or no dot dont give you a answer. You must bolt down the heads to be sure.

Bild 192.jpg

Bild 193.jpg

 
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coilwire

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I haver 2 sets of 4v heads, 4v quench heads #0h27

4v open heads 1m23.

They are stamped in the rocker valley As soon as I can find my book I will try and get all the numbers.Hope this helps.

Jim

 

david020278

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The stamped on the rocker valey are the date code.

0h27 = 1970 aug. 27

1m23 = 1971 oct. 23

When the date code 1970 and earlyer you have closed chamber heads after 70 OC or CC heads...

I haver 2 sets of 4v heads, 4v quench heads #0h27

4v open heads 1m23.

They are stamped in the rocker valley As soon as I can find my book I will try and get all the numbers.Hope this helps.

Jim

 

coilwire

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shooting from the hip there. Have to clean this shop and find my ford engine books.:blush:

Jim

 
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Christian,

All of the above response are "right on" but I am not sure that the "answer" to your question is obvious.

I like to identify the 351C heads as being one of two types - - Closed (Quench) Chamber or Open Chamber. There are some differences in combustion chamber volumes within those types which would go to the "heart" of your need for an answer as to which heads you have. My interpretation is that you need that information to figure compression ratio. When considering compression ratio, it is important to appreciate there is not that much difference between the chamber volumes within a given type (Quench or Open).

Other than observing the combustion chamber, the best way to identify the specific type is by casting number. As David stated in an earlier post (where he provided an excellent picture), the casting number is found on the underside of the head (when mounted on the block). In David's picture, it shows a casting number of "D1ZE" on one end of the head and "DA" on the other side which equates to a casting number of D1ZE-DA. This identifies the head as an Open Chamber Cobra Jet head as identified in the links in the other post. The link will also give you the chamber volume for that particular casting number.

Again, all of the responses are correct and very good information but just want to make sure that your SPECIFIC question is answered to include (my belief) information germane to why you are asking the question.

Hope this helps.

BT

 

coilwire

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Cobra, don't know if you helped hassi01 'but you helped me. at least now I know that my heads are CJ heads. Do you know the torque specs for a 4 bolt main. The book I have does not cover it. I need the specs and sequence.

Thanks

Jim

 
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Jim,

We probably should have started a new thread for this but my reference shows 95 - 100 on the head bolts. Boss and HO is three step 40, 80 and 120 foot pound.

Tightening sequence would be:

1. Two center bolts (middle and bottom of head)

2. Two bolts to the right of the center bolts

3. Two bolts to the left of the center bolts

4. Two end bolts to the right of the center bolts

5. Two end bolts to the left of the center bolts

Reference: Chilton Mustang 1965-73

Hope this helps.

 

FastE

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Cobra, don't know if you helped hassi01 'but you helped me. at least now I know that my heads are CJ heads. Do you know the torque specs for a 4 bolt main. The book I have does not cover it. I need the specs and sequence.

Thanks

Jim
If you are asking for the Main cap bolts on a 4 bolt block they are as follows - 1/2 x13 bolts 95-105 ftlbs

3/8 x 16 (out side bolts) 35-45 ftlbs

Start at the center and work your way out.The old "Off Highway" book does not give specifics on a patern for the outer bolts.I have always torqued the inside bolts(1/2 x 13) to specs first and then gone back and done the outside(3.8 x 16) bolts last.Never any issues.

 

hassi01

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Hello,

Thanks for all the information, I have really learned a lot of 4V heads now. The number inside is 1G12 this would then be a 1971 and probably a closed chamber head.

But as you told me also, to be shure I will dismount my heads on Monday and check the code with the given links here.

Based on the model of my heads I will have then a given compression rate with the 408 stroker from GHP of:

Part Number and oversice Cylinder Head Volume

58.0cc 64.0cc 68.0cc 76.0cc

14212+020 12.80 11.88 11.34 10.40

So finally the performance of my engine is also defined by the compression rate and in worst case the open camber would have 76 cc. So my compression would be 10.40.

Due to the low compression rate of 10.40 would you say this is also o good combination and the performance will be OK ?

 
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david020278

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Christian,

when you build a street driven engine go not to high with the compresion ratio.

With the mild cam that you will use (xe252h??) you become problems with pinging ....

I think you can go hoter with the cam.

Here you can calculate the dynamic compresion ratio:

http://www.wallaceracing.com/dynamic-cr.php

For a street driven car , go not much higher than 10/1 static compression.

 
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Hemikiller

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The number inside is 1G12 this would then be a 1971 and probably a closed chamber head.
Getting back to the 4-dot, I have two complete M-code engines and one set of heads. all ar CC heads and have the 4-dot. However, 1G12 decodes as July 12, 1971. It's a crap shoot as to whether they are CC or OC heads since the Q-code was introduced in May '71 and M-code production stop date is indeterminate. Ford also continued to make replacement casting for some time.

If you want to keep the motor running, just pop the intake off and use a mirror to get the casting number off the underside of the head. Post the casting number and we can tell you exactly what you have.

 

hassi01

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Hello,

Happy new year to all of you !

On the 3-rd of January I have planned to dismount the intake now and check and post you the casting number.

I think today and tomorrow I need to relax due to some heavy Sylvester parties here in Tirol.

Hope you all had also a nice night :)

 
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