AC Delco R43 Spark Plugs
 

I found a set of never used AC Delco R43 Spark plugs with a date of 1995 on the box, are these considered "nos" and weren't they used primarily for 302 small blocks in '69? Do they work better than the Autolite plugs I'm currently using or are they just correct for that motor? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif



http://i14.photobucket.com/albums/a3...n/DSCN4026.jpg

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https://www.yenko.net/ubbthreads/imag...ouguysrock.gif Thanks!

Re: AC Delco R43 Spark Plugs
 

A little on the cold side for a street 302. I like the R44S or R45S AC's. I ran the Autolite 86's I believe and they worked good.

Re: AC Delco R43 Spark Plugs
 

------JMHO,,,,But Autolites will stay clean longer and generally run better than the same plug in an AC box. I used them exclusively in Red Alert for 8 years........Bill S

Re: AC Delco R43 Spark Plugs
 

Yep, Autolites are good! https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: AC Delco R43 Spark Plugs
 

I have always used the Autolites, https://www.yenko.net/ubbthreads/imag...iggthumpup.gif what I'm trying to find out is do the R43 plugs have a specific application or is it a preference thing. https://www.yenko.net/ubbthreads/imag...lins/dunno.gifThanks guys.

Re: AC Delco R43 Spark Plugs
 

I would stay away from the newer ac delco plugs they are junk

just my .02.......... Rich

Re: AC Delco R43 Spark Plugs
 

[ QUOTE ]
I have always used the Autolites, https://www.yenko.net/ubbthreads/imag...iggthumpup.gif what I'm trying to find out is do the R43 plugs have a specific application or is it a preference thing. https://www.yenko.net/ubbthreads/imag...lins/dunno.gifThanks guys.

[/ QUOTE ]They are a colder plug used in the 69Z's and the L78 motors. I don't know of any other application they are used for. Maybe some earlier solid lifter motor corvettes. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif I don't know if the 1970 High Perf. motors used them or not. Maybe a Yenko Deuce guy will chime in. I would say more of a racing plug.

Re: AC Delco R43 Spark Plugs
 

I'll try and grab my AC plug book & see what all they fit...

Re: AC Delco R43 Spark Plugs
 

R43's were the standard plug installed at the factory for all 69 Z28's. In 1970 they went to the R44 for the 350 LT1 Z28's. Here in the Chi Town burbs everyone I know seems to prefere the NGK XR5 over anything..I have them in my 70 Z and my very good friend also runs them in his 69 Z. I believe that Darren (Darren X33) also runs them in his 69 Z.

Re: AC Delco R43 Spark Plugs
 

I also agree with Rich (Mr Chevy) that the newer AC R43 plugs like the ones you have Bart, aren't very good. If you want to run the correct plug that your car is supposed to have, then look for a set of vintage AC R43's like these with the 4 green rings....they are much better than the ones you have.

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Re: AC Delco R43 Spark Plugs
 

Problem is, Delco doesn't make their plugs any more...simply repackages them...wanna say they're made by the same place that makes Champion plugs? The side cut Autolites work ok. When we messed with plugs on the dyno, my beloved AC's were horrible...no matter of the heat range, they all SUCKED...stuck in an NGK, and I've never looked back...

Here's some plug info I posted a while back:

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<u>Z28 &amp; LT-1 with 186 heads:</u> my AC book calls for a C43 or an R43 plug, and the NGK site says-

Standard, V-power (3/8" reach, 13/16" hex, projected tip, gasketed seat):
XR4 / 5858
XR5 / 3332

Race, V-power (3/8" reach, 5/8" hex, projected tip, gasketed seat):
R5670-6 / 4449
R5670-7 / 5034
R5670-8 / 5657
R5670-9 / 6468
R5670-10 / 6702

<u>L78 &amp; L72 with 840 heads:</u> my AC book calls for a R44 or a 44N plug, and the NGK site says-

Standard, V-power (3/4" reach, 13/16" hex, projected tip, gasketed seat):
GR4 / 2635
GR5 / 2851

FR4 / 5155 (same as GR plugs, except for 5/8" hex)
FR5 / 7373 (same as GR plugs, except for 5/8" hex)

Race, V-power (3/4" reach, 5/8" hex, projected tip, gasketed seat):
R5672A-8 / 7173
R5672A-9 / 7405
R5672A-10 / 7942

R5671A-7 / 4091 (same as 5672, but with non-projected tip)
R5671A-8 / 4554 (same as 5672, but with non-projected tip)
R5671A-9 / 5238 (same as 5672, but with non-projected tip)
R5671A-10 / 5820 (same as 5672, but with non-projected tip)
R5671A-11 / 6596 (same as 5672, but with non-projected tip)

<u>L78 &amp; LS6 with 291 heads:</u> my AC book calls for a R43T, and the NGK site says-

Standard, V-power (.460" reach, 5/8" hex, projected tip, tapered seat):

UR4 / 6630
UR5 / 2771
UR6 / 7773
YR5 / 7052 (same as UR plug except w/ non-projected tip)

Race, V-power (.460" reach, 5/8" hex, projected tip, tapered seat):

R5674-6 / 4449
R5674-7 / 5034
R5674-8 / 5657
R5674-9 / 6468
R5674-10 / 6702

R5673-6 / 2405 (same as 5674, except w/ non-projected tip)
R5673-7 / 2817 (same as 5674, except w/ non-projected tip)
R5673-8 / 3249 (same as 5674, except w/ non-projected tip)
R5673-9 / 3442 (same as 5674, except w/ non-projected tip)
R5673-10 / 4050 (same as 5674, except w/ non-projected tip)

Re: AC Delco R43 Spark Plugs
 

I appreciate the information on the plugs, https://www.yenko.net/ubbthreads/imag...iggthumpup.gifI wasn't 100% sure they what they were for. I'm not going to use them myself because I'm happy with the Autolites. I may just list them on Ebay but if anyone can use them, pm me.

Re: AC Delco R43 Spark Plugs
 

I use the NGK's also. Always used the older R44S Delco's but Rob (these young guys) made me switch. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif The R43's will probably do pretty good on Ebay.