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Discussion Starter · #1 ·
Hi all
This question may be so basic that it doesnt' even belong here, but indulge me please. I acquired a "built" chevy 350 bored .60 over torque plate. The engine has a comp 12-250-3 cam and an Edelbrock 750 cfm performer carb, Weiand intake manifold, older style HEI ignition, and Sanderson headers. That's about all I know. So, does it make a big difference which spark plugs I use. I want to change them, simply because I don't know how old they are, and they seem a little bit fouled. What do I need to use, or what must I avoid. Is there any risk with the plug being too long? Any help is appreciated. John
 

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Do you know the compression ratio? The only reason i ask is sometimes domed pistons sometimes cause a problem.

Do you know what the heads came off?

if they are standard wedge heads i would just go with spark plugs for something like a '79 Camaro with a 350. The reason being that car should have an HEi unit and the plugs should be the correct heat range and gap.
 

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Discussion Starter · #4 ·
I don't know the compression ratio. I can easily remove, and then replace the existing plugs, with the same type. One of my thoughts was if I could upgrade to something better, but I don't know if there really is a "better" spark plug. I was looking at the splitfire plug, but really don't know if it's any better. Is the cumulative opinion to simply pull a plug, and replace it with the same thing? I agree with the comment about the '79 camaro engine. I'll bet that that's close to where my engine came from. I also know that I have a 10 bolt posi rear end, that I was told came from a Camaro, so it's quite possible the engine came from the same car. I'm pretty sure the heads are cast iron, nothing special. They may be camel hump heads, there is a grooved carving in the heads that looks like two humps. I also notice that on the passenger side, there is only a single threaded hole drilled into the head. The hole is on the upper end, toward the outside of the engine. I don't know if that helps. John
 

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San Carlos, eh? I grew up in Belmont. My old stomping grounds so to speak.

I went to the ACDelco site and they gave R45S for my 350HP 327.
 

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Santa Clara. We have lived here for 25 years now.
The only way to tell exactly what heads you have is to pull the valve cover, there is a cast in number right about in the middle.
I think the double humps were on a few different versions. Look at this web site....
This site has head numbers.
 

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Discussion Starter · #8 ·
Vaughn, That is a great site for future reference. I do need to figure out what block and heads I have, since it will make things much easier in the future. That, and I've been cruious to know exactly which engine I have. Santa Clara...my old stomping grounds. I went to Santa Clara Univ, 84-88.
John
 

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Discussion Starter · #12 ·
Randy

I also work in RWC, and I drive my car to work about once a week in the dry months. If you ever see a pink "hot rod" style Bel Air racing up and down Veterans Ave on my way to Kohlweis Auto Parts, that's me.
John
 

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BELLA57 said:
Randy

I also work in RWC, and I drive my car to work about once a week in the dry months. If you ever see a pink "hot rod" style Bel Air racing up and down Veterans Ave on my way to Kohlweis Auto Parts, that's me.
John
I'll look for you, I use Maple and Veterans getting over to 300 Bradford each day.:cool:
 
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