I have had great results with NGK BCPR6ES...Whats the timing @ ?
Info...8.0:1 CR with 6 PSI @ 32* timing. Also aluminum heads, no stat.

I've been running about 32-33 degrees of timing. Dist is locked.

10:1 compression 91 octane fuel, seems to be about the best I can get.

Perfect...try those,$2.99 each.

thanks.
would those be the equivelant to the Bosch Platinums I am running now. the motor runs really good, and I don't wanna mess anything up.

Its just a standard plug. Or if it runs good as is leave it.

I'm curious if the the plugs I'm running are too hot. My engine is 10:1 CR with AFR heads, Crane Hi-6 box and PS-92 coil. AFR's website suggested to start with Autolight AR3935, which is what I've been running. This is their racing plug and the hottest plug in this series. Should I cool it down with a cooler plug?

This is probably a dumb Q,
but will I notice a loss in power with a cooler plug?

No loss of power with a cooler plug.

Is it the threaded section that is shorter on the R42TS's??? That is most likely because of the Merlin heads. You don't need that exact plug. Just something in the same heat range.

Griff,
I had R42t's not the R42ts's, maybe that was the difference.

The R42T was noticably shorter threaded area then the Bosch's.

The threaded area is the same length. Only the tip sticks out a little more.