blown bbc plug

whats a good ngk starter plug for a 555 bbc, dart 345 heads, water in system, 12:1. were gonna start it with 32* and 10 psi. i was thinking ngk -8s or are they too hot.
thanks in advance

 

thanks mike, ive worked on tad, tafc, top fuel, and nitro funnies but this is my first personal blown ride. had to have something to feed the beast inside now that im not part of the carnage carnival anymore. your article on plug reading is spot on, i just wasnt sure since this thing is pretty low boost if a hotter plug wouldnt help it some.

 

bbc

my chevy could run the 5671 or the 6061 hemi plug. The 6061 could run quite a bit leaner. I never compared the power, when I was on a good track I always ran the 6061.

 

Depends on the ignition system you are running. MSD electronic, I would use a 5671-10. With a mag, you could run the 5671 are the 6061.

 

msd, i dont feel the need to go mag until we plan on running more boost. this combination should never see more than 14-15 psi.

 

we will be running the 5671 for the long ground strap. i just dont feel the need for a mag on anything making less than 15 pounds. the msd should fire 10 or so pounds reasonably.

 

Mike would you use a 5671 in a screw bae at 60 psi if the tuneup kept good cad on the plugs?
On my Chevy I could take a 5671 and clean all the cad off the face and it would start to get a little frosty white.
Same tune with a 6061 it would have maybe 20 percent cad on the face which is what I like.
I need to reduce costs per run and the 5671 is a good way to do it. I guess most people with screw hemis run them on kill so you don't see it often.

 

plugs

if you can use them i have 48 new 5671a-9 plugs that i'll never use.

 

I know of at least one Pro-Extreme team that uses the 5671 plug. PSI-C with Hemi.

 

I never said that! I can tell you that a blown alcohol BB Chevy with a MSD electronic ignition will make more power and run faster with a 5671 than a 6061. With a mag, I never found any difference in the performance of either. I'm no spark plug expert, but I have tried this on the dyno and on the track a few times. Same results every time.

 

i can certainly use those plugs if your willing to separate with them.... 713-202-9835 Jason

 

It would seem to me that the 6061 requires more energy to produce the same amout of spark in the chamber. Could be because the 5671 plug has a smaller electrode with less porcelain aroud it and a thinner ground strap. Like I said, not a plug expert and never looked for the difference. I know plenty people that have good success with the 5671 with engines like the OP was asking about. Just my experience with electronic ign. and blown alcohol. If someone has a MSD7 and 6061 plugs that works good for them, thats all good also.

 

Could just be that the longer electrode holds a little more heat, certainly easier to fire a warmer plug than a cold one. Warmer in temperature not heat range.