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LT-1 Spark Plugs

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Old Apr 9, 2016 | 01:11 PM
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Default LT-1 Spark Plugs
My 1970 rebuilt LT-1 engine currently has Delco R45S (extended tip) spark plugs.

Would you keep the extended tip Delco R45S plugs or change them to the regular Delco R45 plugs?
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Old Apr 9, 2016 | 03:10 PM
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Originally Posted by clatgeo
My 1970 rebuilt LT-1 engine currently has Delco R45S (extended tip) spark plugs.

Would you keep the extended tip Delco R45S plugs or change them to the regular Delco R45 plugs?
I run the R45S in my L46 with the original LT1 style pistons. No problems. How do your plugs look ? If they are good why change ?
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Old Apr 9, 2016 | 03:37 PM
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OEM plugs were R43 so your 2 heat ranges hotter than stock. Back in the good old days w didn't get much mileage out of our R43s so we would go the R44 plugs but, today there are extended tips that should allow a proper heat range plug to survive longer. Do you have to have AC plugs?
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Old Apr 9, 2016 | 03:56 PM
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R45 is to hot for 11:1 compression .. OEM was an R43..
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Old Apr 9, 2016 | 03:56 PM
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NGK
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Old Apr 11, 2016 | 12:05 AM
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Originally Posted by babbah
NGK
For the past several years I have been using NGK plugs. Their quality is excellent, never had a problem.
The quality of the Delco plugs were terrible, I was forced to look for something else.
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Old Apr 11, 2016 | 12:28 AM
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Originally Posted by Barry's70LT1
For the past several years I have been using NGK plugs. Their quality is excellent, never had a problem.
The quality of the Delco plugs were terrible, I was forced to look for something else.
NGK's are quality plugs. I run the Iridium's all my cars including my 67 BB. Well worth the extra bucks!
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Old Apr 11, 2016 | 01:34 PM
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Had bad luck with Delcos starting in the 90s
Switched to autolite never had a bad one
No need for expensive spark plugs
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Old Apr 11, 2016 | 02:01 PM
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What benefits/symptoms are you guys noticing when you say that some plugs were terrible and others were of good quality?
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Old Apr 11, 2016 | 05:11 PM
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Originally Posted by AboveTheLogic
What benefits/symptoms are you guys noticing when you say that some plugs were terrible and others were of good quality?
In my case, the last set of Delco plugs I bought had the ground electrodes a different length on each plug as well as not being aligned with the center electrode. The gaps were all off as well.

I had to straighten, file and align all the electrodes. If Delco couldn't assemble the electrodes correctly, then what else was screwed up that you could not see.

I just use the regular NGK plugs, not the expensive versions.
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Old Apr 11, 2016 | 05:57 PM
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Originally Posted by AboveTheLogic
What benefits/symptoms are you guys noticing when you say that some plugs were terrible and others were of good quality?
I've tried them all and the NGK's just seem to perform and last a long time.
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