The posted 'G' heads will serve you well, Small block.  I wouldn't lose any sleep over the thickness of the deck surfaces on these.
 
In rebuilding your engine, one of the 'things' you may want to dig into is the topic of 'steam holes'.  Note:  the term 'steam holes' is a misnomer;  it refers to water circulation through the engine water jacket.  The head gaskets you purchase from many manufacturer's will have directions indicating that IF your block and cylinder heads do not have these holes in the water jacket between the front two and back two cylinder areas they should be made.

After digging through the Forum archive of countless past postings of threads on the topic of 'steam holes',  I have come to no longer add these holes to the engine block or the cylinder heads of the y-blocks I'm rebuilding.

What manuals or other sources will you be referencing as you work through your y-block rebuild?

Regards,


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

  Thanks to all the  information all you guys that posted  on this subject I  have  found the facts  I wanted to know!    My buddy and I went over to his garage  to check the ECZ-G  1958  heads!
We found  that  they are the later  posted heads!    When we checked them with the calipers  it looks like they have not been  milled and they look to be in real good shape.
 They should  be  worth rebuilding , This is good because when  his heads were pressure tested  they a  found one  of the  original heads on the 1964 engine is cracked! 

Hi Small block.  Click the link below to see a thread that delves into the ECZ-G cylinder head topic.  -The short of it is that there are three (3) series of 'G' heads. 

One series was made in the '57 model year only, has different intake and exhaust porting than the others (different sand cores were used at that foundry for making the heads) and none of these cylinder heads were 'posted'. - These 'G' heads have the small letter ECZ-G identifying them.

The second series was produced and used on all '57 model year Ford 272, 292, and 312 engines AND Mercury 312 engines until May of 1957.  The casting letters identifying these were large letter ECZ-G.  These heads were not 'posted'.

The third series of ECZ-G cylinder heads were cast beginning in May of the 1957 model year.  These, too, were used on all Ford 272, 292, and 312 engines for the remainder of the 1957 model year production AND on the Mercury 312s for the remainder of 1957 AND for all of the 1958 Mercury model year for the 312 engine!  These cylinder heads are 'posted'.

Clicking on the link identified below and working through the entire thread will give you pictures of what the difference is in appearance of the small and large letter ECZ-G is and that link also references another link for identifying 'posted' and un-posted cylinder heads.  
http://forums.y-blocksforever.com/Topic113734-1.aspx

As y-block billy said previously, I would not be concerned as to whether your heads are posted or not posted.  Unless you are building a y-block with a supercharger or turbocharger, I doubt that you'll experience a problem.  Whether your heads are 'posted' or not posted is something to know as you turn to a machine shop to have them milled.  As John Mummert's cylinder head page indicates, the maximum recommended material removal amount is different for the two species.  The 'pads' on your heads adjacent to the spark plug holes and below the exhaust ports were 1.000 inches when originally produced by FoMoCo.  Measuring those pads with a micrometer will let you know IF they have already been milled previously and how much.  -Many machine shops do not know this 'pad' information about y block engine because of its earlier era and their available information.

Hope this helps.   


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

    Does the  Y block engine  have  date codes  like  the later model ford parts do,, if so  were do I find them and  how do I decode  the  date code!
 The  heads were supposed to have  come off a 1958  292 engine but I have  no Idea what body it was in! 

On the non posted ECZ -G heads, our man Ted says restrict milling to 0.025"  Others have indicated they have milled them more in the past, but for any kind of performance use that's a risky move..


Paul

Those heads are fine as long as you are not supercharging, the later ones dated after May 57 are posted. just dont mill too much off the non posted ones, I think most people say not more than .035" for the non posted.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Thank  you for the  information on the  heads , and  glad to  help any body I can
The heads  I have  are the  ECZ-G  heads  so they may not be the  most desirable, sounds like the deck of these heads are real thin! 

Small block:  INTERESTING comments from the old Ford mechanic about the HD 292 truck engines.  Because of the limited HD truck application, I find that few owners of y-block cars and light duty trucks are knowledgeable about the ins-n-outs of this Ford application.  The sodium filled valve stems with their 7/16 (?!?) diameter are probably another interesting discussion.

You indicated that you've got a set of '58 vintage large intake valve heads.  I've attached a link to John Mummert's web site with the listing of different y-block heads and their original application.  Click the link below...
http://www.ford-y-block.com/cylinderheadchart.htm

It's AMAZING the number of different heads that Ford produced for the y-blocks between 1954 and 1964.  At one point, it was a matter of what transmission the engine was to be mated with or whether it was to have a two barrel or four barrel carburetor.  In '57 they started simplifying the whole thing a bit...

Welcome to the site, and thanks for making the time to share what you have picked up for info on the why-fors of HD 292 engine application. 


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

They went with the shorter rod for the heavy duty truck engines which was 312 length (which was a good thing if you wanted heavy duty rods in a 312) due to the compression height of the top of the piston, I believe the pistons were also forged instead of cast to handle the heavy loads and yes they were not intended for high rpm, most or all had the governed carb distributor setup which I believe was factory set to 3800 rpm.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

      Thanks  for  all the   information The  rods in the pickup are C2AE!    The  valves in the heads on the engine are real small. I have a set of heads off a 1958 engine with the  big valves so he will probably  use them!
A bout the rod length I was just talking  about the reasons  with a old ford mechanic a while a go because  I was curious about the same thing,  his explanation  for shortening the rods on the Heavy duty 292 were as follows
1   A larger compression height  made more  room for ring lands making  the  piston stronger
2  The taller piston had better support under heavy load, this  avoided the piston  tilting helping to get a good ring seal!
 I asked  him why not   just  extend the lower skirt of the  piston and use the long rod ? he  said  when they experimented with  that they found  the  lower  skirt  was likely to crack! 
 About the  re design  of the 292  for heavy duty use, he told me that  Ford was  disappointed in the Super duty  engines, in both  performance and the way they slurped gas!
There were guys that would  refuse to buy the  super duty engines, they wanted an engine that  would get better  mileage!    The 292 302 and 332 were still in demand