HI,
what heat range do you guys run in your LA-motors? Stock for mine would be a Bosch number 10 which is a super hot plug. I am a little worried that this would cause detonation... I am considering to use a Bosch 6 or 7 now, which is NGK 6 or Champion 9 or 10.

What we are talking about if you want to read it all:

Quote:

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-late 318 LA-block (factory roller lifters)
bored .040 over (after sonic check)
mild stroker crank 3.51 stroke
-some dished pistons @,010 deck height.
comes out to 344cui, 9.5 compression with the heads mentioned below.

302 heads with 2,02 in and 1,8 exh valves (3 angle valve job with back cut... pocket porting... gasket matched to intake)

Edelbrock Performer intake
Edelbrock Performer 600 carb

Comp CAM 264HR-12
DUR @.050:
210 220
MAX GROSS VALVE LIFT .480 .480
DUR @ .006 TAPPET LIFT 264 274
LOBE SEPARATI 112.0
installed straight (As far as I understood they grind them advanced).

roller rockers with 1.6 ratio (cam specs are with 1.5 ratio)

Hooker comp headers

dual exhaust 2,25"

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Greets
Flo

depending on your driving habits but I wouldn't use anything colder than an RN14YC and would for general driving RN14YC plugs.

I started with the NGK 4's, then the 5's, then the 6's, and I have been running the cooler 7's for over a year now. The cooler 7's helped with detonation and they allow me to run on 89 octane (9.7:1) and my plugs are clean with the FBO ignition.

on my 9.7:1 416 cuin i was running autolite 65's but changed them out to the autolite racing AR53

With you using bosch's I would start with a bosch that crosses over to a champion 12. A Champion 9 equivelent would for sure be too cold & your CR isn't very high & you didn't say street or strip but I would start at 12 & see if you can access the thread that might be in the archives that had EXCELLENT plug reading pics(heat range & mixture)

Ok, as recomendations are all over the place and plugs are cheap I will start with a Bosch number 7 and see if they foul...
Greets
Flo

I was running Autolite #65 in my warmed over 318 ( stock stroke) and they were a little hot, #64's seem better.

I finally found the article about reading plugs I saw quite a while ago.
http://www.dragstuff.com/techarticles/how-to-read-plugs.html

In my mildly built 318, with Champion RN14YCs, there is color on the ground strap all the way to the base ring. So the above article would indicate mine could go one step colder?

-Dave

that's it, a comprehensive a plug article as you could ask for. With an innovate LM-1 A/F ratio meter with an rpm converter a person is all set to get your mixture dead on & wring out every last bit of horsepower that can be had.