Dart Heads, Spark Plugs?

[mr_blasto]

I have a motor with dart heads and figured I would consult their website for spark plug recommendations. According to them, I need to be using one of two autolite plugs AR3933 or AR3934, both of which are racing plugs.

The problem is Autozone doesn't seem to have them. They can't order them either and they don't cross reference to a plug they carry.

These plugs are available from summit, but I am hoping to find a local solution. The plugs have:
.750 inch reach (regular plugs seem to be .708)
Don't have a resistor (normal plugs do)
14mm threads (pretty standard)
gasketed seat (most seem to be tapered)
5/8 inch hex (pretty standard, but I found a delco plug that almost worked, except for the 13/16 inch hex).

Anyone else run into a similar problem? The autolite catalog says these plugs are for racing bbc's, hemi's, and porsche's (IIRC). But I looked up a non-racing plug for a bbc and it showed one with a tapered seat, .708 inch reach, and was a resistor type plug. I am so confused, someone straighten me out . BTW, I don't have a stereo of any sort so a non-resistor plug shouldn't be an issue.

 

[4X4HIGH]

I run a set of AFR heads and i run an NGK #5155 plug in mine.

These are, .750" reach, 14mm thread, gasket seat, resistor plug, 5/8" hex

 

[bigblock72]

Shouldn't be hard to get a plug that will work. Try any of these NGK #s: 6953, 6962, 2756, 7373.

Try and keep the heat range at a 5 or 6 for a NGK. The 5155 is a 4 and might be a little too hot for your combination.

 

[mr_blasto]

Awesome. I will have so many part numbers Autozone won't know what hit them. Thanks guys.

The 6953 and 7373 seem to be identical to each other. Just as the 2756 and the 6962 seem to be identical. I have a hard time deciding what cereal to eat in the morning... choosing between seemingly identical spark plugs makes me feel like I am missing something. (Reminds me of the joke, "How do you keep an idiot in suspense?")

Also, though I am not using a stereo, I still need a resistor type plug to avoid interference with the ECM right? Also, all the plugs recommended so far are projected tip, whereas the autolite plug recommended by Dart is not. Is this significant or incidental?

 

[bigblock72]

The only difference between the numbers is the gap. The 2756 and 6953 have a .044 gap or 1.1 mm, hence the -11 at the end of the number.

The projected tip is a trivial at your horsepower and intended usage. If it was ran WOT coninuously or made a large amount of power (boost, nitrous etc.) then it would be a good idea to run a non extended tip plug to keep the tip from glowing and causing preiginition. The extended tip is good for a driver to help keep the plug from fouling.

 

[mr_blasto]

I just got the 6953's, but the gap seemed closer to .040. I gapped them to .045 anyways. As always, thanks for the help.

 

[Stomis]

Advance stocks a load of autolites.

 

[justwhatido]

Napa

Find your local NAPA dealer.

Better'n most parts houses. Just tend to be pricier around here.

 

[mr_blasto]

Problem solved. Bought plugs and put them in. Thanks guys.