Spark plug checkup.

[TJ's GMC]

Hi guys, just pulled the NGK's from my 305E with a 600 cfm 4 barrel, Pertronix hei, and dual exhaust. 10 degrees initial timing and gap at .040-.043. Not bad. Couple of them are shaded a little. All are burning a tad bit of oil from the valve guides. But I am impressed. Runs good. Put some AC delcos in and will test those. So far I have noticed a little more low end response. Overall no feel of better acceleration. Gapped at .055. They have a cross over for NGK's so I may end up eventually going to their version as I have never had one bit off issues with them. Plug numbered 1 - 6 from left to right.

[Jmclendon]

Hello,
Are those B6s?
I'm only asking because those were one of the types suggested as substitutes on a site that I was looking at.... Pickings are slim over here. But, I seem to be able to find ngk.

[TJ's GMC]

GR4's

[1972RedNeck]

Originally Posted by TJ's GMC

Hi guys, just pulled the NGK's from my 305E with a 600 cfm 4 barrel, Pertronix hei, and dual exhaust. 10 degrees initial timing and gap at .040-.043. Not bad. Couple of them are shaded a little. All are burning a tad bit of oil from the valve guides. But I am impressed. Runs good. Put some AC delcos in and will test those. So far I have noticed a little more low end response. Overall no feel of better acceleration. Gapped at .055. They have a cross over for NGK's so I may end up eventually going to their version as I have never had one bit off issues with them. Plug numbered 1 - 6 from left to right.

Do you think the plugs were responsible for the added response or just the increased gap?

[TJ's GMC]

Originally Posted by 1972RedNeck

Do you think the plugs were responsible for the added response or just the increased gap?

More than likely the plug and gap. I'm not sure how the plugs differ besides brand and the fact the AC can be gapped at .060.

[1972RedNeck]

Why can't the NKG's be gapped to .060"

[TJ's GMC]

Originally Posted by 1972RedNeck

Why can't the NKG's be gapped to .060"

They probably could be, but some spark plugs can only be gapped so far before you start to have issues. I had this happen on my 292. Gapped the NGK plugs to .055 and the engine would Pop at idle. To much gap for the plugs. When Pete mentioned the AC's were used in 478's and were specifically made to be gapped fairly wide I got them, and they were half the cost of the NGK's.

[Sponge]

Do you need a special tool to remove those?
Or just pull the spark plug wire and take it out?

[AZKen]

Sponge:
In general: Twist plug boot before and during pulling on it. Never pull on the wire itself. Use a deep socket or a plug socket to remove. No "special" tools required. Any plug that is the correct length and threads will work. Set at MFG recommended gap. A spark is a spark. You get no "performance" from a spark plug. Low end or high end or middle end.

[TJ's GMC]

Originally Posted by Sponge

Do you need a special tool to remove those?
Or just pull the spark plug wire and take it out?

I just grab on the boot and pull it off there. Plugs I use require a 13/64 deep socket. I used a 3/8 ratchet and extension.