what plugs for EQ magnum heads

[Rapid Robert]

I tried some autolites & ngk's & one was too short & one was too long! what should I get, maybe one or 2 heat ranges colder than stock (will be raced). thank you for your time. RR

 

[12many]

Ran Autolite 3924’s in the EQ’s I had on my 410. Worked fine. Didn’t have any issues with them Ran the race versions of the 3924’s as well again no issues. That number would be a good starting point at least

 

[64 Sportfury]

I've been running NGK 7373 on a EQ headed 318/390 stroker/9.49 to 1 comp and a small hyd roller cam with Pro Flo 4 EFI for 7500 miles and they color nicely.

 

[Bewy]

Raced? Unless it is circle track [ WOT for periods of time ], turboed, blown or using nitrous, you need the factory heat range, which is 5 in NGKs.

 

[Rapid Robert]

yes it will be raced (1/3 mile dirt circle track) duration 15 to 30 minutes

 

[Bewy]

Then I would use NGk 7s. If they foul at idle, use 6.

 

[Rapid Robert]

Plugs I had on hand, I tried autolite 5325 & they were too short then autolite 3924 & it was too long then autolite 5224 & it was too short (about 4 threads in the head still showing in the combustion chamber on the short ones). I had champion rn12yc in my other EQ magnum & today I checked one & it was short also (same as the other 2 short ones I checked earlier today). it ran strong but I cant help thinking it woulda been stronger with the threads flush.