Dennis: First are ECZ-G heads very hard to find in Australia?.  If so it might be worth a gamble if you can get them "cheap". As noted by Ted, the engine he was dealing with was high compression. Most likely had domed pistons & or the block had it's deck milled down. If your engine block is stock & with stock pistons, for normal street use it might be o.k. On the other hand, if the heads need a complete rebuild or the head surface needs further cleanup milling, probably should pass on them.. Good luck    


Paul

Thanks for all the helpful information guys! At this stage it seems like quite a gamble to purchase these heads, especially since they are not posted. Thanks Ted for your sharing your real world experience, it’s always good hearing first hand accounts.

I’ll keep you guys posted is anything develops from this.

Thanks again for the amazing wealth of knowledge!


Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

Here is a past thread discussing adding posts to the ECZ-G heads.
 
http://forums.y-blocksforever.com/Topic47592.aspx
 
It’s really only the ECZ-G ‘unposted’ heads that requires any discussion about adding posts.  All heads made after the ECZ-G heads have posts while the heads preceding the ECZ-G heads are cast in such a manner that the intake runners provides the needed additional deck support.  The ‘G’ heads were the first of the big valve / big port heads which has a lot to do with why the castings changed.
 
With that being said, it’s only the ECZ-G ‘unposted’ heads that requires the addition of ‘posts where there are none.  All small letter G heads are unposted while it’s the big letter G heads that come with and without the posts depending upon when and where they were cast.  The Ford shop manual specifically limits milling of the 1957 heads to 0.010” but it’s generally accepted that you can get away with as much as 0.025”.  I’ve had personal experience with as set of unposted G heads that were milled 0.060” and both heads had a continuous issue with both head gaskets failing repeatedly.  The gaskets were failing on the two cylinders on each bank that had the posts added in the later cast heads.  In this particular instance, the heads were switched out to a pair of milled ‘113” heads and the head gasket problem simply went away.  This was an engine that had the compression ratio bumped to 10.5:1 so it was already at the octane limit of available pump gasoline in the best of circumstances. Hence the need for posted heads.

Lorena, Texas (South of Waco)

I know the thread but I haven't found it, yet.

Here are some describing the operation but not actually showing it being done.

http://forums.y-blocksforever.com/Topic47013.aspx
http://forums.y-blocksforever.com/Topic33877.aspx


Lawrenceville, GA

I just took about .047 off a set of 55 ecg heads to take them to interceptor spec.I thought it was only to much if heads were going to see a lot of hard abuse or a supercharger?Mine are low mile heads so I wasn't concerned with corrosion in water jackets.I think if you are just going to use as a weekend driver its fine.My thoughts
Dave

Not a difficult job. Involved drilling a hole in the top of the head. Threading it and screwing a piece of 1/2" (?) allthread in until it was up solid against the deck side of the head, not through. Then cutting off the top of the threaded rod flush with the bottom of the rocker arm area. I don't think its necessary unless you plan to add boost.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Billy's point is a good one about the static compression ratio that most of us are dealing with when rebuilding y-block today. 

I attempted to find the thread in our Forum Archive that was done several years ago by a Forum member on how to post un-posted G heads.  It was a step-by-step description with pictures of installing posts in the un-posted G heads to prevent deck flexing.

Our Forum moderators, Ted, Charlie, or John, may be able to re-issue that thread.  It was well done and complete with the info. needed to effect the modification.  In my Archive search titled 'posting heads' I was able to go back 50 web pages, but that was only two years of entries that were pulled-up using that search title.

While the head posting may not be necessary, it could certainly give Dennis the peace of mind that he deserves after all the work he's put-into his engine and truck.  


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

I beleive the head milling John is talking about is for supercharged applications with higher combustion pressures, in a non supercharged application I think more can be removed. I think the intake pad area needs to be milled .54 or .64 of what the surface milling was cant remember exactly off top of my head (must have been milled too much)!

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?

Just had a chat to the owner of the heads and he said they measure 0.955-0.960 inch. So that would equal roughly worst case 0.40. He also said they are not posted😩.

What do you guys think? Too risky, or would you think they might be ok for an engine that only gets used a dozen times a year? (Providing the surfaces are all even and square)


Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

As I recall the un-milled heads will have pads about 1" thick. Those look like a pretty heavy cut. You can see they milled into the port area quite a bit.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire