Spark plugs?

Anyone know the difference between WR7CC and W8CC plugs? Which ones best for 2 litre CU engine?

 

The difference is the heat rating of the spark plug (whereby a 7 is a hotter plug than the 8 )

but the correct plug for a bog standard type 4 is the W8CC

I generally run 7s in engines that I've upped the comp ratio on

 

W8's are hotter running plugs for most normal driving conditions as well as colder climate and lots of stop and go traffic.

W7's are colder running plugs for warmer climates and extended/high rpm highway driving.

Apparently )

 

Ben, have you got a chart that you use for plugs?

Edit - found one... and yeah, you're right... I'd got my figure confused

 

So I'll go with the 8's then? Cheers guys