Spark Plug Information
 

While looking for spark plugs for my Vortec heads I ran into this AC chart and thought I would share. I had been using to short a plug in mine and found that the Vortec heads (iron) need the LTS style.

R - Resistor

4- 14mm thread

3- heat range

LT - Long reach, .715" (18.16 mm), Tapered Seat

T - Tapered Seat Shell Design

TS - Tapered seat with extended tip

LTS is a long reach tapered seat plug with a extended tip.

TS it a tapered seat plug with a extended tip.