Question about cylinder head 351c 2V

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dkgd91

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france
My Car
ford mustang 1971 V8 351 C
Hello i have some question about the cylinder head on my 351 Cleveland 2V

It's is normal that some of the hole for the rocker arm are more wider than the other ?(i'm talking about the hole on the red square on the picture)

Sorry for my bad english i'm not a native english speaker

Thanks for your answer

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There are differences between a 351C 2v & 4V heads...

The size of the intake runners causes some of the differences, but the main reason is performance.

Production 2V heads in the areas you pointed out allow for oil to drain back into the valley faster...

Production 4V were designed for more performance, under higher RPM valve springs get hotter, so oil is used to cool the springs.  OIL in the 4V head can rise up to a higher point to cool the springs.  Only drain back via drain holes in the lower corners & push rod holes...

Same for some early 351c 4V blocks had extra hole in the rear corner to allow the valley to drain in cornering G-forces

D1AE-CB_01.jpgD0AE-N_02-2.jpg

Screen Shot 2021-07-11 at 11.48.32 AM.png

 
Thanks for your answer 

So the main reason for that modification on my 2V's it's for performance

But On some hole in the left cylinder head i Can see it was handmade (1st and 2nd picture)

And on the right cylinder head they still have Iron cast on the middle of the hole( 3rd and 4 picture) do i need to take off the matter ?

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Thanks for your answer 

So the main reason for that modification on my 2V's it's for performance

But On some hole in the left cylinder head i Can see it was handmade (1st and 2nd picture)

And on the right cylinder head they still have Iron cast on the middle of the hole( 3rd and 4 picture) do i need to take off the matter ?

View attachment 53003

View attachment 53004
Not for performance on a 2V, just better drain back on a street motor...  the valley generally drains back on to the crankshaft...  extra oil for normal driving is okay, on a high RPM motor will reduce HP, increase windage...

What you are seeing on these pictures is 'flashing' from the casting process.  This topic is like talking about which 'OIL' is better ...   If you are going to completely disassemble the heads then it is good [not needed] to de-bur de-flash the extra iron...  and clean the heads...  Not going to take them apart the flashing is okay ot leave.   If building a performance motor I would take the heads apart and de-flash the metal.

jm2c

 
There are differences between a 351C 2v & 4V heads...

The size of the intake runners causes some of the differences, but the main reason is performance.

Production 2V heads in the areas you pointed out allow for oil to drain back into the valley faster...

Production 4V were designed for more performance, under higher RPM valve springs get hotter, so oil is used to cool the springs.  OIL in the 4V head can rise up to a higher point to cool the springs.  Only drain back via drain holes in the lower corners & push rod holes...

Same for some early 351c 4V blocks had extra hole in the rear corner to allow the valley to drain in cornering G-forces

View attachment 53000
Just for info, that block was a D0AE-J block. The oil return holes were as seen, no rough casting hole as seen at the front on the "L" blocks. I am not aware it was just a 4V block, but merely an earlier 1970 block. I sold it believing that these were bad blocks, wish I hadn't now.

 
Just for info, that block was a D0AE-J block. The oil return holes were as seen, no rough casting hole as seen at the front on the "L" blocks. I am not aware it was just a 4V block, but merely an earlier 1970 block. I sold it believing that these were bad blocks, wish I hadn't now.
LOL, the picture is your image... from our older posts.    have no proof that it's only a 4V block, but I personally only found them on early 4v's 1970ish & boss blocks.  Having worked at fords if there was a need for a part they used what ever was available so you could find them on a 2V [a 2 block block is a 2 bolt block]...  We in the day looked for 70 4v's only to get all of the better parts... I still have a jan/feb casted motor L block that has the extra holes.

If anyone knows how different block cast numbers were allocated across the 4V & 2V motors it would be interesting...  other than a 71 Boss L block.

Are you saying the front drain hole below the distributor at the valley floor?  see picture.  flashing happens along the casing parting lines everywhere.. some is remove by hand, most is cut away during machining processes.  During engine prep/blue printing you would remove it for a number of reasons, and chamfer oil holes. 

Screen Shot 2021-07-11 at 8.14.43 PM.pngScreen Shot 2021-07-11 at 8.14.43 PM.png

 
LOL, the picture is your image... from our older posts.    have no proof that it's only a 4V block, but I personally only found them on early 4v's 1970ish & boss blocks.  Having worked at fords if there was a need for a part they used what ever was available so you could find them on a 2V [a 2 block block is a 2 bolt block]...  We in the day looked for 70 4v's only to get all of the better parts... I still have a jan/feb casted motor L block that has the extra holes.

If anyone knows how different block cast numbers were allocated across the 4V & 2V motors it would be interesting...  other than a 71 Boss L block.

Are you saying the front drain hole below the distributor at the valley floor?  see picture.  flashing happens along the casing parting lines everywhere.. some is remove by hand, most is cut away during machining processes.  During engine prep/blue printing you would remove it for a number of reasons, and chamfer oil holes. 

View attachment 53009
Yes, those are the ones. Pretty rough looking, but did the job. These were not on the J blocks as you know. As for 2 or 4 bolt mains, any block could be either. It would just be an added machining op to drill and tap the extra holes as the bosses were already cast in. Any Cleveland block can be reworked to accept 4 bolt mains......... if you can find the caps!! As for Boss blocks, I have two listings. Mustangtek only show Boss blocks as D0AE-L 4 bolt mains, but the other shows D1ZE-A or B as well as D0AE-L.  

 
correction ... my 1970 Jan/Feb 4V is a D0AE-J and it has the extra drain holes.

what I'm interested in is a motor disassembly of an original 1970 351C 2V motor and it's casting data and parts

 
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