<VV> Effect of Reduced Quench on Jet Size and Timimg

[NicolCS at aol.com]

Welcome to the wonderful world of more efficient head design.  12:1 is  still 
way too rich, my '66 EFI car is regulated to 14.8 which is still on the  rich 
side of the high fuel economy target ratio of 15:1 to 16:1.  At 14.8,  I have 
no trouble at all with pre-ignition under any condition; climbing grades  at 
103 degree ambient for example.  Just like yours, this engine also has  the 
.032 squish modification and 9.25:1 C/R.
 
Just to double check the AFR, I'd take a look at the plugs and check the  
color of the insulators.  Light tan color is what you want and the  surrounding 
metal should not have a thick carbon coating.  One way to get  the AFR down 
without going to smaller jets is to install exhaust headers.   This has the 
*unfortunate* effect of increasing horsepower but what that means  is that you will 
need less throttle for a given roadspeed, i.e. more fuel  economy.
 
If you have darker-brown color plugs on all six, there's no  reason to doubt 
the AFR gauge and you need to install smaller jets (or headers)  to get the 
AFR up to the high 14s.
Craig Nicol