Need opinions on plugs.

A429 headed 522. 13:6:1. 730 lift. 733 on dyno at 38 with 114 at 6800.
It's went 6.02 this year in bad air.... 3300da and bad humidity.
I've been running a 100 shot delayed on a leash board .08-1.2 delay off the line for 5.90 class.
Plugs have looked good and we brought 2* back in based off the plugs and mph.
Changed plugs every run. Towed to lanes,etc.

i ran a 6.0 class on motor with 38* back in it two weeks ago.
Question is.... Why are #3 and#7 rusted looking??

6.0 class was all motor on 114 with 38. Then the car sat for two weeks. Compression check tomorrow.

Rust means there is moisture somewhere.
Compression check and pressurized coolant system check.

Some fuels can cause stuff like that to rust VERY quickly if there is any moisture. That moisture can come from the air itself if the engine sat for a couple of weeks.

Last it ran was on the 13th after a race. I had 112 in it at the time. Cranking compression last night all came in between 249-255. It just strikes me odd those are the only two cylinders like that. Garage is insulated. Open headers.

IMHO, you are running to cold of a plug for racing fuel only. They might work well with N2O, but I think a 7 would serve you much better if you're running it all motor.

3&7 exhaust valves were probably open wile it set. I had some issues with copper head gaskets leaking that looked like that before. Any missed coolant?

Those are #9s. I run some index races with a 100 shot delayed 2.2 seconds and also run 6.0 index on motor. I change from 120 to 114 when I do.


Maybe 1/2" of water loss after 8- 10 passes cool40.

Keep an eye on them two cylinders but being on opposite banks it's not likely an issue,IMO. Even if it's putting a little water through it you can use a block sealer and fix it.

I'd check the torque on the head bolts if you're digging into it. May as well cover all the bases before you decide what is wrong.

Thanks guys. I'm going to race it at YBN and then probably pull it before hunting season starts. Well over 350 passes. I'm sure she is getting a little tired.

Curt wrote:IMHO, you are running to cold of a plug for racing fuel only. They might work well with N2O, but I think a 7 would serve you much better if you're running it all motor.

X2 big time! 9's way too cold. I agree on the 7's.