Re: 13-1/2 to 1 compression ...on the street?

Stan Weiss wrote:

> As Nate said   "Aluminum heads shed heat"
> "all other factors being equal, allow you to safely run a half point
> more compression on the same octane fuel than do cast iron."
> 
> But since most Aluminum heads are after market or late model factor
> design and most are some what better engineered / more efficient
> combustion chamber design, they can run more compression.

There are a lot of REALLY ****ly-engineered aluminum heads available, 
too. They're not in any way guaranteed to be better than well-prepped 
stock iron heads in terms of chamber design, but they will still have a 
thermal conductivity advantage.