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siii8873
10-02-2011, 11:05 AM
I'm working on an engine skip and want to change my spark plugs. I have a few new sets but no cross reference for which ones would be for a 7:1 head. The book says Champion N8,
anyone know?

I Have,
Bosch W7DC
NGK B6ES
MOTOCRAFT AGS32C f4
jac04
10-02-2011, 01:52 PM
Check out:
http://www.ovlr.org/OVLR.alt.parts.html
TeriAnn
10-02-2011, 09:29 PM
I'm working on an engine skip and want to change my spark plugs. I have a few new sets but no cross reference for which ones would be for a 7:1 head. The book says Champion N8,
anyone know?

I Have,
Bosch W7DC
NGK B6ES
MOTOCRAFT AGS32C f4

For both 7:1 an 8:1 engines up through 1984, CHAMPION RN11YC 4 (nearest to original) or NGK BP5ES (a good option).
siii8873
10-03-2011, 06:21 AM
The plugs I have all came with series trucks. What is the difference in these from recommended? I put the Bosh plugs in they match what was removed.
jac04
10-03-2011, 10:28 AM
For both 7:1 an 8:1 engines up through 1984, CHAMPION RN11YC 4 (nearest to original) or NGK BP5ES (a good option).
Any idea why the SIII green bible lists Champion N12Y for 8:1 and Champion N8 for 7:1? I had no trouble finding RN12YC plugs locally.
disco2hse
10-04-2011, 12:03 AM
Any idea why the SIII green bible lists Champion N12Y for 8:1 and Champion N8 for 7:1? I had no trouble finding RN12YC plugs locally.

IIRC correctly the 12 is slightly hotter than 11. The difference probably has to do with different fuel concentrations in different countries.

Champion standard plug is the 4 and 5 is hotter but the NGK 5 is standard and the 4 is hotter. Makes it all fun :rolleyes: