ngk zfr5n correct? please help

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discharger1332

discharger1332

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i bought some NGK zfr5n plugs for my slant 6 and when i went to install them i noticed they are 5/8 size and the tip is much longer than the autolight 66's that came out. just wanting to double check before i finish my tune up that these are the correct plugs you guy are running in a 73 slant? I plan to remove the washers but that will make the tip even longer.
please help
 
Yes, those are the plugs with the extended tip. They put the tip or spark a little further into the combustion chamber. Slant sixdan swears by them, others have mixed reviews. I have them in my car now, seems to run ok with them. Dont have much of an opinion on them either way.
Do you have a drool tube head ?
 
discharger1332 said:
i bought some NGK zfr5n plugs for my slant 6 and when i went to install them i noticed they are 5/8 size
Click to expand...

Yes, you will have to use a different spark plug socket to install them than you used to remove the previous plugs.

and the tip is much longer
Click to expand...

Yes, that's the whole point of using them.

I plan to remove the washers
Click to expand...

Good, that's the right way to do it.
 
thanx guys, i got it tuned up yesterday. seems to be running really good now. still blows carbon while warming up but once warm all is good.
 
"Blows carbon while warming up" means your choke system needs attention. Most likely your choke pull-off is either not adjusted correctly or it's faulty. Article is here. If the pushrod from your choke thermostat on the exhaust manifold to the choke lever on the carburetor is bent other than its original straight-line Z shape, ditch it and put in a № 1231 Electric choke kit.
 
No, it's not because the fast idle is too high.

Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.
 
thank you, I just read through that. now I am thinking maybe i have some other issues though. I am not sure if my timing light is broken or what but when checking the timing the dot was all over the place, and not consistent at all. I was able to get the car running much smoother and no more hesitation off idle but now am wondering what is up with the timing?
 
so i think i might order the choke conversion, i do not see a way to adjust the choke spring and it closes pretty hard. the link you posted shows a different part for 73 and up. mine is a 73 but the stoke looks the same as on my 72? is the 1231 correct for my application?
also the u shaped link is pretty tweaked, could this be my issue?
I cant add any pix now but will today, and I appreciate your help.

IMG_2464.JPG


IMG_2465.JPG
 
U-shaped link looks to be in fine condition and readily adjustable. Electric choke № 1231 is correct for all Slant-6 1bbl carbs '60 thru '73. Starting in '74 the № 1234 is correct, and the 2bbl "Super Six" is № 1232.

(Your stock '73 choke thermostat is not the same as the '70-'72 items, which aren't the same as the '74-up or '66-'69 or '62-'65 or'60-'61s...)
 
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