‘68 Spark Plugs - Guidance

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Nov 21, 2020 | 07:10 AM

HDRIDER957

Thread Starter

Heel & Toe

Joined: Sep 2009

Posts: 22

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From: Hillsborough NJ

‘68 Spark Plugs - Guidance

Hi all, in my regular maintenance I’ve replaced my spark plugs on my ‘68 327/300. I got the ‘68 I’m May ‘20 so I’m still learning about this great car. I bought replacement reproduction AC44 spark plugs from Corvette Central. When I replaced the plugs, I found AC 7 plugs, most were good, but 2 the electrodes were badly worn down. Question is am I okay with the AC44 original plugs or should I be considering something else?

Thanks for your help!!

Nov 21, 2020 | 09:37 AM

speedreed8

Melting Slicks

Joined: Oct 2006

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From: Texas

The 7 was for the 200-275 hp engines. The 44 is the correct plug for the 300 hp I believe.
I think you’ll find most people run the R45 now if it’s just a cruiser. I prefer NGK’s. But you should be fine with the 44s.

Last edited by speedreed8; Nov 21, 2020 at 09:51 AM.

Nov 21, 2020 | 09:47 AM

jeffstuarts

Instructor

Joined: Nov 2013

Posts: 128

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From: Bloomfield Township Michigan

Quote:

Originally Posted by speedreed8

The 7 was for the 200-275 hp engines. The 44 is the correct plug for the 300 hp I believe.
I think you’ll find most people run the R45t now if it’s just a cruiser. I prefer NGK’s. But you should be fine with the 44s.

I think you meant "R45" not "R45T' since the T stands for Tapered seat and will not fit a '68 with original head. The "5" heat range is a good fit for 300 hp engines used for normal street driving.
Jeff

Nov 21, 2020 | 09:50 AM

speedreed8

Melting Slicks

Joined: Oct 2006

Posts: 2,417

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From: Texas

Yes you are correct. R45. Corrected

Last edited by speedreed8; Nov 21, 2020 at 09:52 AM.

Nov 21, 2020 | 10:49 AM

HDRIDER957

Thread Starter

Heel & Toe

Joined: Sep 2009

Posts: 22

Likes: 4

From: Hillsborough NJ

Thanks for the quick feedback. I’m going to be starting it up and taking it out with the new plugs. With those 2 plugs pretty worn down I’m expecting it to run a little better!

Nov 21, 2020 | 06:11 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

I agree with the NGK's, if you select their irridium plugs. Those puppies will last 100K miles or more....which means that you don't have to go thru the nightmare of all the ignition shielding 'stuff' but ONCE during your lifetime.