SPARK PLUGS?..

[6FIVE_STANG]

I have a 289 and i just installed a MSD setup a few days ago, I need new spark plugs but i dont know what to get! (size, tip material, heat range??...)
what should i get?

 

[fasttback]

First we need to know what heads you are running? Also knowing your compression ratio may help you choose a plug temp to start?

There are numerous sites that have some useful info (here are a couple):

http://www.centuryperformance.com/spark.asp

http://www.dragstuff.com/techarticles/how-to-read-plugs.html

 

[6FIVE_STANG]

STOCK 289 HEADS.

 

[fasttback]

18mm thread. My last set I used Autolite 45 (heat range 5) on an Mallory ignition. Compression was 9.5 to 1. It's best to read your spark plug after running it.