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Discussion Starter · #1 ·
Could too hot of plugs make my engine run lean possibly? I'm running a pretty much stock 350 (stock heads/cam) with a 650cfm edelbrock electric choke. I switched the jets/rods to the non choke model cause it was running lean. But it still seems to run a little too lean at cruise. Does fine when I punch it but I'm getting grey plugs.
 

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Take a look at this.. www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp The plug heat range has to do with how much heat the plug draws away from the cyl. Being too rich or lean is a fuel air mixture problem. Having the wrong plugs could make it harder to diagnose. The rule of thumb I was taught was one range colder per every 100 hp over stock. Find a plug book at the local parts store and go from there.

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...Dennis
"The '69, the '96 & the club"
 

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Discussion Starter · #3 ·
Well I'm running .070x.047 rods with .101 primary jets at sea level. This is what a manual choke 650cfm Edelbrock carb comes with (.100jet though). I guess I should go a stage richer? Would changing the step up springs have much to do with it?
 

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Discussion Starter · #5 ·
600 650 whatever the 1406 is the one I'm running (I think...lol).

Anyhow, whats the stock plug heat range for a 350???
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by 67chvy:
Anyhow, whats the stock plug heat range for a 350???<HR></BLOCKQUOTE>

AC R44 would have been std on most 350's I believe. An LT1 runs one step colder (R43).


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...Dennis
"The '69, the '96 & the club"
 

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You need to post the year of your engine and what type of ignition system ... For example, pre-HEI might run R44 at .035 gap ... mid-70 HEI would run R45 with an .045 gap ... and as you go own, there are other combinations ... Also, are you using any kind of gas additives ???
 

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Discussion Starter · #9 ·
I'm running a proform HEI with an accel brute coil and new condensor and module. And I think I'm running .045 gap with R44 plugs I think. Not completely sure about the plugs right now. It's just a standard stock 350 in my 67 Camaro.

NO gas additives. I've never cared for em except the octane boost stuff if you need it.

The engine does run mildly hot at about 190. When you turn it off it'll soar to 200-205. Then it won't start but that's just the starter coil getting too hot.

I did try the pink springs (ones above the orange ones) for step up springs but that didn't change anything. So I think I'll just go with .067x.047 rods. If I can find em.
 

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For a basically stock engine, your plugs should be fine ... The engine temp going up a few degrees after sitting is expected since no cooling is taking place ( that's why cars with elec fans will run after you turn car off ) ... I suspect that your timing is too far advanced ... DOes the car ping any? ... Too much timing have give you surging sensation when cruising ( especially if a little lean ), and too much timing also makes car harder to start ... Try backing off a couple of degrees ...
 

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Discussion Starter · #11 ·
It's at 0 degrees. I'm in Phoenix though. I am running an electric fan and I agree, I expect the temp to go up a little since it shuts off with the car. There is a little surging at cruise but not much. The rods I think are just barely too lean at cruise since when I hit the gas it goes like a bat outta h*ll.

I guess it just seems strange to me that I'd need to go rich beyond what a manual choke carb is outta the box.

You think I should go a tad richer with the rods at power too? The Edelbrock book says to.
 

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The good thing about the edelbrocks is that you can make these changes without taking the carb apart ... I would go ahead and change the rods ... The other thing about the timing is how much advance are you running ... springs may be too light ... advance kicking in too quick ... these are things you can look at ... sometimes tuning becomes a bit of trial and error ... I would try rods ... timing ... advance springs ... these are all the things that make playing with cars GREAT!
 
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