97 Vortec 350, 510" comp roller, mildly ported heads. I plan on nitrous in the near future and need to know what plug to run. The vortecs take a deep plug that has the extra threads on it.
So I want to run a temp range that equals an AC43 or AC44. What plug number do I need? I am not real brand specific... would prefer ACs but any brand would be Ok.
I had this same problem with my Darts on the turbo engine. There are not alot of options for what you are doing, but there are a few. I asked the guys at the part store to look up plugs for a mid eightys vette and they were able to find the long plugs doing that. Then we found the coldest plug they had. I think it was a champion high performance of some sort I ended up with. It has a tapered electrode type design. If you need the number, I can look for it tomorrow. Thing is that the aluminum heads take different plug types than most cast iron heads due to galling issues. But, the vortecs might be the same by some stroke of luck.
If your gonna run nitrous go with some NGK race plugs. Dont let the name scare you, they'll work fine for daily driving too. If your spraying like a 150 - 175 hp kit you should be fine with some NGK #6's. The only thing with running a colder plug on a regular basis is they will foul out abit earlier. Depending on how much you drive the car you might wanna just use them when your gonna spray it.
Im not sure what you mean by long reach. If your refering to the length of the threaded part of the plug then yes. They have a longer threaded end then a conventional plug. Its required in all of the aftermarket heads I use on all the engines I build. Though I have yet to build a vortec headed engine, judging by the pictures Ive seen of the combustion chambers, the shape of the chamber and the way that the spark plug boss extends into the chamber I would think that it would need the longer threaded plug.
The 6 in an NGK series refers to the heat range and is a fairly "hot" plug, at least as hot or hotter than the 45. My cross chart shows a AC 43 being similar to an NGK 6 heat range plug. Run that plug with a 200 shot and it will be your last. For nitrous we use NGK heat ranges from 8 for a mild shot of 120 up to 11 for 400.
You need a short fat electode plug to run a 200 shot and I would say at least in the 9 heat range for an NGK. You do not under any circumstances want a projected nose plug.
If you would take the time to list the plug reach (which you are calling the thread length), seat type and thread diameter needed I can look up a couple of plug options for you. I would assume your looking at a 3/4 reach 14mm diameter thread. Feel free to PM me.
The 6 in an NGK series refers to the heat range and is a fairly "hot" plug, at least as hot or hotter than the 45. My cross chart shows a AC 43 being similar to an NGK 6 heat range plug.
i was under the impression that I needed about an AC43 temp range as I thought that was colder than an AC45. Doesn't a stock 350 from 1980 or so call for an AC45? and they recommend an AC46 if oil fouling is occuring from rings guides, correct?{because it runs hotter and burns off the oil.}
So it sounds to me if the plugs threads and thread depth are the same the NGK#6 is what i need. Am I correct?
Go here and click on how do I choose the right plug. That will get you going. Within that link is a search engine for finding the correct plug for a stock application. You should be able to get a baseline plug to run without nitrous. Tell me what you come up with.
Ok before this get too confusing. The engine we are dealing with is a 97 vortec 350 that has at least a larger than stock cam. The stock heat range recommended by NGK for your application TR55 V-power racing plug, which is equivlent to your engines stock plugs heat range in AC Delcos line. With our LT1 engines given cam and compression combinations, reverse cooling, and the fact we limit our spray to 150hp thats what works for us. Given the fact that your spraying a 200 shot through a vortec engine I would have to agree with Rick WI and start with a #9. Depending on your compression ratio and cam duration you may be able to tune down to a #8. The only way you will know would be to make some passes on the #9's and read the plug. As far as the numbering system as it relates to the plugs, different manufacturer use different numbering systems. NGK's line happens to get colder as the numbers get larger. All the V-power plugs for your engine come in the long reach design. You'll probably have to visit your local speed shop to get a set as autozone usually doesnt stock them.
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