Spark Plugs : which ones to use 4age ?

[jondee86]

Typically a silvertop turbo has high compression and low boost, so one
heat range colder on the standard plug should be fine for normal
everyday use. Maybe go two ranges colder on race day

However, 4AGZE => 4AGTE conversions will typically run 15 psi or even
higher boost, so plug choice gets a bit more complicated. You can try
experimenting with other plugs until you find one that works for you. If
it can ignite the mixture reliably under all boost conditions, and the heat
range falls somewhere between fouling and vapourising the electrode,
then you are good to go

Best to talk to people who are running similar setups, and have a read
of this link to get a few ideas :

http://www.lextreme.com/sparkplug.html

The silvertop head design is quite different from the 16V GZE design,
so you can't take it for granted that one will suit the other.

Cheers... jondee86