We have been using a R5671-7 or -8 in our motor, with B1-BS heads......I have been trying to find a "PEANUT" plug that will be a decent street plug, something thats forgiving with start ups but yet still cold enough to make some power and be able to tune ????

I'm wondering whos running these heads on the street and having decent success with a certain plug ???

Also as you can guess, these heads in a B body with headders is quite a challenge to get plug in and out, along with keeping the boots off the headder tube, thus my reason for asking for a peanut plug.

I know NGK made a good street plug, but after a fair bit of searching, I still cant find it.....maybe something like a BES-8 or ???

Can't help you with the peanut plug deal.... but I always found the colder plugs would foul on me while street driving. My motor was slightly above 11-1 complession and anything colder than about a 4 or 5 heat range in an NGK, the car would start popping while street driving. I never saw any performance change at the track, just on the road.
Always thought it could be because I'm using a dominator and need the extra heat to burn the fuel at lower RPM???
You're right... I've got the same heads in a Dart and plug changes are a huge pain.

TTI sells a modified plug socket for their B1/BS headers you might try. Scott Koffel told me about another one that was being sold commercially with a unique design. I always wanted to try a peanut or "shorty" plug w/my BS heads but couldn't find any at the time(this was a few years ago). The other option($$$$)is a set of custom headers...or the TTI ones.

Try Autolite 3911 or Champion RC9YC

3933 Autolite my