Does anyone have any information on how thick the deck is on a ECZ-G Head or how much can you cut the head to get the CC's lower?

Gary Ryan San Antonio.TX.

Gary;

I'm sure you will get other responses on this, but the rule of thumb I use rests with the rectangular bosses on the heads. If they have not been milled/shaved before, they should mic over 1.000", but not by very much. It's my understanding that if the bossses on your heads are much less than 1.000", you run the risk of the valve hitting the piston top depending upon the type of piston and head gasket (thickness) you use.

Rono. 

  Ron Lane,  Meridian, ID

Though the typically reported volume is higher, my unposted Cleveland (large letter) heads had not been previously milled, and after a .005" clean-up cut, the chambers averaged 65-66 c.c.s.

6 VOLTS/POS. GRD. NW INDIANA

The information that i am looking for is the thickness of the head surface to the water jacket, like between the combustion chambers.  How much can be milled off before you run into problems of cracking?

Gary Ryan San Antonio.TX.

Gary, i dont know that thickness you mention as it would vary between castings, to my knowledge they dont crack on the flat surface but in the valve seat area. The amount that can be machined safely is more a matter of small amount .030" ? and be able to align intake holes with head or more and have to machine intake side of head to align bolts. Others can add thier expierences but certainly varies with head, block and intake combinations.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

My 113 heads are milled .030-.035.  The machine shop didnt keep track of the first milling, so therefore the range.  With that much off, and significant block decking, you may need milling on head intake flanges.  I had the block decked .028, and intake flanges .046.  .046 off the intake side removes the top step in the flange.  The static CR ended up between 9.1 and 9.2.  .060 over 292.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

I chopped 0.05" with no problem, but those heads were -113.


Hyvinkää, FI

Ted Eaton will provide definitive information when he gets time. 

Unposted G heads with too much compression will flex just enough to allow combustion gasses to get by the head gaskets and into the cooling system.  So not only are you dealing with how much can be milled re cracking but also all other combinations that increase CR.

You gotta have the right tools and know how to use 'em.

TC - Austin, Texas

Here is a link to a discussion on this subject.

http://www.y-blocksforever.com/forums/Topic16300-3-1.aspx  

In it Ted says for unposted G heads .010" is factory recomendation but it is generaly accepted that .025" is the max. Mike

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Thanks for all the infomation, Maybe i need to rethink things.

Gary Ryan San Antonio.TX.