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Short life for spark plugs, 429 SCJ


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My 429 SCJ is completely rebuilt, everything is computer balanced; new 11.3.1 forged pistons, 0.40 oversized bore, Cam Research cam, polished but not turned nodular crankshaft--maintaining STD dimensions, SCJ rods with new bolts, Crane Roller Rocker arms with poly locks, hardened push rods, heads lightly portered to clean up castings, all new associated valve train parts, etc. Use combo of 101 octane and 94 octane ethanol free fuel. 

Despite the newness, it chews up a set of Motorcraft spark plugs in a hurry. I drive it 2-3 times per week on short hops for errands. But after 250 miles, it needs new plugs--old ones get fouled in a hurry.

Anyone else have the same experience? Recommendations for better plugs? 

Thanks, tim

Mach 1 1971 429 SCJ OK stamp July 2020.jpg

Tim: Restoring 71-73 Ponies, Restoring People

139A1893.jpg

 

 

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What heat range? If all is good with the ignition, the maybe you need hotter plugs.

20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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The short trips are your problem, need to thoroughly warm it up once in a while. Pedal to the metal, blow that stuff off the plugs.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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I'd verify that the timing and curve are correct first. If they are correct I'd find out why the carb is running rich (blown power valve, wrong calibration, float level too high, etc.).  Chuck

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