tips on changing spark plugs, 390, 4 speed & Calif Smog all intact

Hello All,

I am looking for any tips or tricks in order to change the spark plugs in my 67 GT, 390, 4 speed. It has stock exhaust manifolds, A/C and all the Calif Smog still intact. :pray:

Do the Swivel Spark plug sockets - made by various companies ( one is ARES) actually work for this application?

I appreciate any thoughts and suggestions.

Happy Holidays.

I don’t know about the smog equiped cars. But I pull the engine mount bolts on one side at a time. Use a board and jack the engine up a little. Replace plugs than switch sides.

The GT500 owners have posted about this numerous times over at the SAAC Forum.

Paraphrasing an amalgam of their posts plus re-posting a photo from Cobra owner Dan Case of the tools that he uses below -

This is all about the drivers side… loosen the master cylinder… use a soft spark plug boot tool to remove plug wires… use a swivel spark plug socket, a 3 foot long extension, and a ratchet drive socket and remove plugs… place some Anti Seize compound on the threads of all the new plugs prior to installation… cut a length of vacuum hose and slip it over the tip of plug for the extension needed to thread new plugs in the socket & finger tighten them into the head… tighten with a 3/8th ratchet… use soft spark plug boot tool to snap wires back on.

In Mr. Case’s tool photo you’ll notice that he found or made a flexible tool (has screw driver-like handle) in place of the vacuum hose mentioned above.

Don, I think a video of you performing this on a 390 XR7-G with the tall aluminum Shelby valve covers would be great!

  • Phillip

A 3/8" breaker bar with an ordinary (no swivel needed) socket is used to loosen the plugs. You can reach below the master cylinder to get to #7 and #8. GT500 owners have a much harder time because of the tall aluminum valve covers. Thankfully we don’t have those!

It’s not that hard really. I find swivel sockets to be of no use personally for this job. I just use a 3/8 ratchet and extensions, and the 3/8" breaker bar to loosen the plugs.

A big thanks to all! I will try your suggestions.

Happy holidays

All good info., but no one has mentioned smog tubes, the best way I have found is to number the spark plug wires and remove them from the dist. and lay them back over the shock tower, remove valve cover to help get to the smog tubes to loosen the nuts and remove the tubes, then you can get to the plugs like Royce mentioned. Reverse procedure.

great point CatLover. And yes, I have the Smog tubes to deal with.

No mention of the proper number of beers and appropriate swear words that are required.

Yes, the cold 12 pack of Sierra Nevada will be in the Garage frig and I have the swear words all ready to go!

No need to remove the smog tubes.

Well, I used about 2 or 3 swear words per plug, but I’m a former Sailor so I probably use them a bit more freely than most folks (I’m not a swear word horder, I think if you have them you should use them). As for the beers, I go with 2, but I save them for nursing sore knuckles and ego after the job is over.

I still think a video, including swear words and beers, would be helpful and fun!

  • Phillip

I would not suggest attempting to remove the smog tubes. The chances of removing them without damage is almost zero and finding a replacement at any price is almost impossible. Darrell did mine in my 67 GT the other day without much problem.

Maybe pull the valve cover(s) for more room. I just did a 428CJ w/ smog & lift hooks… NOT FUN!