Alternatives to NGK R6725-11s for 650hp on C16
 

As per my other post, I am having trouble getting hold of the NGK R6725-11 plugs.

Are there any alternatives for a 13B bridge port, C16, T51R SPL, 650whp, 1.5bar boost?

Anyone?

What do you race guys use?

I use Denso Iridium's (#35 I think)...not much benefit cost-wise and believe they are just as hard to get hold of, but they work well.

www.sparkplugs.com
They have anything you need, and I've never found better prices.