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Spark Plugs

Bo Dillingham

Well-known member
Joined
Jun 23, 2001
Messages
121
Location
Cortland, NY, 13045, USA
Corvette
1965 crimson pearl (2002 cadillac?)
Be forewarned; This stuff is 30 years old!

According to my memory, and the section on spark plugs in my book "How to Hot Rod Small-Block Chevys" by Bill Fischer and Bob Waar (my copy if dated 1972), the Chevy is noted for "eating" plugs (page 61, first paragraph).

From a previous forum, you may remember that I got quite a laugh at an auto parts store recently when I asked for a set of AC 44's. Formerly a VERY popular plug for small blocks, they are not even made any more. The man sold me R43's for my '65 300/327.

The abovementioned book recommends "Projected core-nose plugs" for the street, as they act as warm plugs at low RPM, and act as colder plugs as RPM's increase.

My question is whether or not this philosophy still applies, or has plug technology brought something new to the game?

My comment (and please forgive this blasphemy) is that years ago a guy who had been racing chevys for a long time told me to try FORD plugs. I did, and a set lasted for years!!! I am not kidding! Back in those days, I was going through AC plugs constantly, and simply by changing to Ford plugs, a set seemed to last forever!

Because it was so long ago, I do not remember what name the plugs were (Ford? FoMoCo? Motorcraft? Autolite?) or what model, but they did work. Since I plan to drive my '65 a lot, and I will have tube headers, I would like to have a long lasting plug. Does anyone have any good information on this topic?

As usual, thank you all very much.
 
From other posts on the subject, here are some plugs that are said to be AC44/AC45/AC46 replacements:

Autolite 75 or 85 = AC44S or AC45S (projected tip versions of AC44/45)

Accel 137 or 138 projected tip (equivalent to AC45S/46S)

Champion J14YC (); J8C = AC44/45, J11C = AC46 (RJ12YC or RJ14YC for projected tip; )


NGK XR4 or XR5 or B4

Denso W14P-U or W9P-U (both resistor-type, I think)
 
I used Autolite back in the '60s. They were stronge as new Champions and lasted as long as AC.
 
ext tip plugs

yes you can run a hotter plug range if you use a ext tip plug because the fuel wash in the chamber will help cool the plug. WARNING,you must index the ground electrode so it is at 9-12-3 o clock position to make sure that the piston does not hit the electrode.
 

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