Dawg:

I tried posting this last night but it wouldn't go.  I'll try again.

On the surface of the head for #3 and #6 cylinders, just outside the fire ring of the head gasket chamber opening, drill a 5/16 hole perpendicular to the head surface.  Tap it 3/8-16 and screw a piece of 3/8 allthread firmly into the opposite wall of the head.  Cut the allthread off a few thousandths long, pein it, and fill off the high spots.  The gasket will seal any coolant that tries to get past the allthread.

JJJ

John - "The Hoosier Hurricane"

Wow! John, you're actually saying to bring the all thread rod from the bottom up through the head where it makes contact with the engine block! That's the solution on the #2 and #3 chambers? The #1 and #4 chambers can be modified from the top down through the rocker arm stands and won't penetrate through the head surface.



Obviously I want to have any modified posts done before I go for the final milling on the heads. So here goes the process:



1. Drill through the surface. Either just off center on the tops through the rocker arms. Or, just outside the fire ring on the #2 and #3 chambers.

2. Kiss the opposing surface to create a flat landing on the opposing wall for the all thread bolt to contact.

3. Tap the newly drilled hole.

4. Thread the all thread rods and JB weld them in place.

5. Do a final cut/file on the all thread rod to flush it with the surface.

6. Take the heads into my machinist for the final milling to ensure the heads are flat, and will play nicely with my block!



Any points that I may have missed? It's probably overkill for my engine, but I figure, if it's worth doing then it's worth doing right the first time so I don't have to wonder in the future.... I'm a perfectionist. Again, thanks for your help.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

Dawg:

Not sure of your description.  There is no need to drill through the top of the head with my solution.  Drill through the machined surface, screw in the all thread until it bottoms snugly against the top of the head.  The spotface would be a good idea, I have always slightly rounded the allthread so it would seek a solid seat.  The rest of your proceedure looks good to me.  I have found that the #3 and #6 chambers require this, the others have intake ports that support the chambers.

JJJ

John - "The Hoosier Hurricane"

Here’s a picture showing the locations of where the factory added the posts to the late ’57 and newer heads. The dotted lines shows the actual post locations while the arrows simply point to the water holes that are used to 'feel' for the posts. Like John, when adding posts to what was originally non posted heads, I’ve only seen it done to the #3 and #6 cylinders but adding the posts to the #1 & #8 cylinders would also be recommended. Although I've only observed this being performed by coming in from the top, adding posts from the deck side does sound less complicated but the decks are likely on the thin side to adequately thread for this. Maybe Vic will comment on if he added his posts from the top or the bottom?

And here’s the link to the thread that particular picture comes from along with some more detail.

http://forums.y-blocksforever.com/Topic6711-3-1.aspx

http://forums.y-blocksforever.com/Topic6711.aspx

Lorena, Texas (South of Waco)

Thanks for the pic Ted. I remember seeing that earlier, and that's how I verified that mine weren't the posted variety!



My only concern with coming in from the bottom is it doesn't look like the post being just outside the fire ring it would add any real support above the combustion chamber during the compression strokes... But I fully admit I'm a newb. The other concern is the lack of meat (metal) on the chamber floor to tap and essentially "grab" the all thread rod. Still a newb and completely defer my opinions to the folks who really know what's going on and have done it before.



And it also sounds like John mentioned in the other post on "Adding a Post" that he only does the combustion chambers from the high intake runner, not the lower intake runners (3 and 6?).

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

Think of it kinda like a bridge. A bridge can be built with a real long span between supports. At some point the span becomes so great that it becomes unstable. To stabilize it, add another supporting structure near the middle of the span. That is what you are doing with the threaded rod. Instead of having an unsupported region of say 2", you have now reduced the unsupported region to 1" which will significantly increase it's resistance to flex. Having it positioned next to the fire ring is probably the best strategy because the post will not flex and keep the pressure tight where it counts.


Lawrenceville, GA

This is what John Mummert suggested to me and what I did. The posts that I added went in the rocker stand above the upper ports, (3 and 6) offset from the center. You are trying to go through right next to a cast wall so you can't go in the middle of the rocker stand. You will try to miss a cast area and be located in the rocker boss. I used 7/16" threaded rod and JB welded at the rocker stand area. Spot faced the roof of the combustion chamber so the bolt hits a clean, flat surface. When the JB weld is set up cut off the thread extending above the  rocker stand. I have not seen any issues on the street. I will be on a chassis dyno Monday morning and see how well they hold during a few nitrous pulls. The last time I was on the dyno rear wheel HP was 363 and 440 lbs of torque. Not bad for a 312 cu in 292 Y-block and 50 year old Henry Ford rods.

  Vic Correnti

Although I've only done this a few times I have always done 3-6 and 1-8. I just figured if Ford did both I would too. Did just as Vic described. Jerry Christenson guided me through it years ago.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico