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what spark plugs?

1724 Views 3 Replies 4 Participants Last post by  SWHEATON
what plugs do I need for my 215 heads? I know there a gasket seat but what reach and heat range do I need? I have 9.8 to 1 compression.
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Here is what i just posted the other day when the same exact question was asked of 215 heads.


Try the R44XLS 1st with those heads as they are the stock replacement AC plug for the 396/325 & 350hp motors ,you can tweak the heat rang up/dn as required from there. The hotter 396/375 hp used the r43xls plugs.

The original plugs in mid 60's-68 & for 69 were either 44n to 1968 & then r44n (r=resistor) from 69 & up. in std tip design. But the xl or xls series are the extended tips plugs that were a later issue plug specifically designed to run cleaner with the tip extended a little further into the combustoin chamber which did help out.

When running the later extended tip design XL/XLS plugs if the motor was idling or at low/low load rpm the plugs would run a little hotter staying a little cleaner but when under a load with a lot of throttle or at WOT there was more airflow and fuel passing by the extended tip of the pulg actually cooling it a bit,it was a good design upgrade at the time for sure.

All these are the longer each plugs which those 1967-68 215 heads should be running.

NOTE:you can also have these AC Delco plug #'s corss ref'd to a plug brand of your choice.

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