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

spamTHISbrp@[EMAIL PROTECTED]
 wrote:
> 
> On Apr 30, 12:05 pm, Stan Weiss <srwe...@[EMAIL PROTECTED]
> wrote:
> > "M.Burns" wrote:
> >
> > > Looking at a nice Pro Street car with 13.5 to 1 compression pistons.
 It
> > > apparently has been at some statewide cruises, rod runs, etc, so I
know it's
> > > been driven. My question is, what kind of fuel must the owner be
running for
> > > the engine to survive. Heard claim that by retarding the timing
somewhat,
> > > pump gas with octane booster works(?)  Race fuel?  Any ideas 
(...from guys
> > > familiar with similar cars or situations). Thanks
> >
> > Cast iron or aluminum heads?
> > Camshaft spec.'s
> > Carb or EFI
> > What might also help is what is the cranking compression of the engine
> > (Do a Compression Test)
> 
> I know a bit about cars, but not why the ?? about Al heads is
> im****tant- is it the fact it's Al and not cast iron, or just that Al
> heads are likely to be better engineered?
> 
> Dave

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.