<VV> Re: Spark Plugs...

[Ed Dowds]

Ryan-
There should be no problem running both resistor plugs and resistor wires. 
I've been doing it for years in all my cars.
The differences in the plugs:
44FF is threaded slightly longer than the 44F
"R" is for resistor (you already knew this)
"S" is for entended tip (this means the center portion of the plug is 
longer, not the threads)
On AC plugs the heat range gets hotter as the number goes up. This refers to 
how the plug transfers its heat to the head, not how it fires. A higher 
number (hotter) plug does not transfer heat to the head as fast. This means 
the tip stays a little hotter to burn off any deposits.
GM usually specified cooler plus on hipo engines. I suspect that they 
thought hipo engines ran hot enough to burn off deposits with a cooler heat 
range.
The down side of hotter range plugs is that they tend to burn material off 
the electrode more easily.
                                Ed