Spark plugs for 429

Having a hard time tracking down NGK spark plugs for my iron headed 429. Pretty mild motor small hyd. Ft cam. Motor goes 11.30s in my 3150lbs mustang. Hit it with a 71 nitrous jet but could only get autolite 45 plugs. Looking for something in the 8 to 10 heat range NGK plugs. Anyone have any stock numbers or suggestions? 18mm thread, non projected tip?

Thanks

I cant say that this is a nitrous plug .But it doesn't have a projected tip like those 45s and I do believe it is a cooler plug than the 45 .Fe guys are running this plug as a replacement for the old bf 32 .The application for the 124 sparkplug is a 361-391 ford truck .And I mean like a f600-f700 truck not a pickup .I have a set of these in my 428cj with no problems .Basically stock 10.5 compression mild cam .Why not take one of your 45s to the parts store and compare it to a 124 you will see the difference .Doug

If you do a search on here I believe there are adapters you can buy to convert to a 14mm spark plug.