DeTomaso Mailing List: June 2000, Message #182

> I've found a pair of closed chamber heads I'd like to buy, but the seller 
> said they are stamped "55" on the ends, and although he doesn't know, he 
> suspects that this number reflects the combustion chamber volume. I doubt
> if 
> I can live with pump gas and 11 + compression.
> 
Why not?  Others have gotten by with 11:1.  The Aussie heads are 
often in the 55 to 57 cc range.  You can always open up the heads a 
bit.  Leave the quench pad alone, polish the chambers, and unshroud 
the valve areas.  

> Does anyone know an easy way to determine if the heads have been milled? A
> 
> measurement that can be made with a couple rulers for example.
> 
The rule of thumb is to not mill an iron Cleveland heads more than 
60 thou or so.  There are a couple of indentations on the combustion 
face (at the ends) that can give an indication of milling depth.  I don't 
have the stock depth handy but can dig out a set of heads and check.  
You really need to cc the chambers as well.  You can use liquid or a 
very fine sand, along with a burette.

Dan Jones