i have bbeen running the NGK R5671A-9's for yrs..
if Jeff says they are worth an improvement..thats good enough for me..
i agree the chrome/nickle base is easier to read then the black phosfate.
i think they have a nickle version fwiw...i just dont know the part number..

what # Autolite plug is a direct cross match from the NGK R5671A-9 plug?

365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
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