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PLUGS FOR A 402


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im getting ready to replace plugs and wires, seems i got nothing right when i switched this to hei 15 years ago so i thoought i would ask you guys. ac r44t at .055 gap. i think i will try autolites. have had good luck with them before. is this the right plug and gap?

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You can run what ever plug you prefer, but remember to make sure they are the correct heat range for your application. The gap will also be determined by your setup. If you need help with this you could do what I did. I decided on NGK race plugs and called their tech folks and went over my setup with them. They got me to the right plug and the right gap.

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You can run what ever plug you prefer, but remember to make sure they are the correct heat range for your application. The gap will also be determined by your setup. If you need help with this you could do what I did. I decided on NGK race plugs and called their tech folks and went over my setup with them. They got me to the right plug and the right gap.

 

I always liked the NGK's and I did the same thing 680HPStroker did except I emailed them. They did tell me that I need to check the plugs to see if I needed to go up or down on the heat range. So far so good. I also have a 402 but I don't remember the part number I have.

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r44t? it would be an R44TS or an R44

 

TS is for 'tapered seat' (if your old plugs aren't teh gasketed type)

 

If you are running HEI.. 'stock' wires won't work. you will have to select a big block application that is 1975 or later.

(HEI came out in late 74 on some applications, widespread in 75)

 

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they are r44t, is this incorrect? do i need r44ts? i thought the 73 s were all electronic ignition. that is usually how i get my wires, 73 monte 454. im not sure if i need tappered seat or gasketed type. i know what each are but dont know which i need. you guys need to quit telling me what you are using and tell me what i need. i guess the r44 (heat range) is correct. i dont know on the rest and ive never seen so many different gaps in all my life.

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Joe,

The correct plug for a stock 402 using AC delco r44ts according to the ac delco book.

 

The correct plug for a stock 402 using autolite is 26 according to the autolite book i think that is a little hot and would go with 25.

 

The correct plug for a stock 402 using champion is rv17yc according to the champion book I don't care to run champion

 

The correct plug for a stock 402 using NGK is UR4 according to the NGK book

 

I checked all years because I did not see it in you post and they all call for the same heat range. If you have done and performane mods that may affect your choice of heat ranges.

 

I would stay with the .035 gap I think that the wider gaps are harder on wires, cap, and rotor. But that is just my personal opinion.

 

Going with wider gaps sometimes changes the spark plug identification. Wider gap plugs sometime have a 5 or 6 in the suffix.

 

I hope this helps

 

 

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