1966 427 425HP Spark Plugs
What would be the best spark plug, gap and timing using pump gas for a 1966 427 425 HP with transistorized ignition?
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Re: 1966 427 425HP Spark Plugs
Champion RN14YC are what I run in L78, driven weekly on pump gas. Gap at 35. Stock cam and TI. Also after market wires, rotor & cap. NOT a flight judged car, but got blue ribbon in new stock Concours Class. -
Re: 1966 427 425HP Spark Plugs
AC R45XLS or equivalent heat range in another brand especially if you can find one that is a non-resistor type. All the major plug manufacturers have cross reference charts on the Web.
You want the most aggressive spark advance map that you can get away with that won't cause detonation, and that depends on the compression ratio. Do you have any idea what it is? So many engines have been rebuilt over the years with "low compression" that most guys really have no idea.
Has the spark advance map been modified? Does it still have the OE ported vacuum advance or has it been converted to full time? The only way to know is to test. There is a recent thread on this subject for L-72, so take a look at it and get back to us with more information.
If you don't already have it get a hold of my 2012 San Diego National Convention Tuning Seminar. It's an easy Web search.
DukeComment
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Re: 1966 427 425HP Spark Plugs
I installed R45 XLS set at .035. I have the OE ported vacuum and running a little over 11 to 1 compression. Just set the timing from 14 degree BTDC to 8 degree BTDC. Seems to be running good.
The problem I am experiencing is vapor lock in this hot weather. The fuel line from the pump to the carburetor is just about touching the lower radiator hose. I am planning on wrapping the hose with heat shielding tape. I know it will need to be removed for NCRS inspection. Don't know if this is a common problem or not. The gas line gets very hot.Comment
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Re: 1966 427 425HP Spark Plugs
Joe,
Converting to full time vacuum advance will help it run cooler, which will help with vapor lock. I would recommend trying that first.
Good luck with your L72!!!
JoeComment
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Re: 1966 427 425HP Spark Plugs
Joe, Nice that you see that the fuel is boiling before it comes close to the fuel system.
The repro '58 to '61 and '62 FI car fuel lines are really causing havoc for same reason. Bends are incorrect. Lines are hugging the valve cover. Hence the old FI's dont' have a chance. Massaging them and wrapping the lines helps. Thanks, JohnComment
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Re: 1966 427 425HP Spark Plugs
John,
Two questions. Is anyone making a correct 62 F.I. fuel line or one that's modified to keep it away from heat? What do you recommend using to wrap the fuel line? RichComment
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Re: 1966 427 425HP Spark Plugs
Have you tried Inline Tube? They always have the most accurate lines from my experience. Inline Tube offers both stainless and OEM material.Comment
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