GT500 Spark plug change procedure.

[1967 eight barrel]

I spent the afternoon helping a fellow pilot from work change the plugs on his 1967 GT 500.  What was supposed to be assisting wound up being  observed.
I thought I'd share a bit of instruction/advice.

You'll need to start by removing the export brace. You'll need a 9/16" combination wrench, 9/16" and 1/2" 3/8" drive socket, ratchet and a 3" extension.
Remove all four of the bolts where the export brace joins the firewall first. You'll need the 9/16" wrench to hold the nuts on the bottom and the 9/16" socket for the bolts on the top.
Next use the 1/2" socket to remove the two bolts that hold each shock to the shock mounts. Then, remove the three 9/16" bolts on each shock tower that hold the export brace in place. Cant the shock mounts to clear the top of the shocks. Then remove the export brace. Set them aside.

Next, remove the valve covers. I start with the left side rear most lower bolt.  Remove the cap from the brake master cylinder. You'll need a large flat blade screwdriver, 16" 1/4" extension, 1/2" 1/4" drive socket and ratchet.  Use the large screw driver to gently push between the brake master and the valve cover.
Slide the extension with the 1/2" socket between the master and the valve cover and get it on the bolt head and loosen the bolt. DO NOT pull the socket away from the bolt. Leave pressure to keep it in the hole on the cover. Get your magnetic pick up tool, put it against the lock washer, flat washer and bolt that holds the cover in place.  Slowly remove the socket from the head of the bolt, trying to capture the bolt and washers on the magnet.  Once you have removed it, replace the brake master lid and lock the wire back down.
Remove the balance of the valve cover bolts. Remove the covers and set aside. I usually set them upside down so the oil doesn't run out on floor or bench.
To remove the plugs I use a 14" 3/8 drive extension, universal and a 13/16 spark plug socket. ( Make sure the rubber retainer is still in the socket) Slide the socket over each plug and remove them all.

Wash your hands and get a beer, Iced tea, coke or a scotch.  Sit down, relax. Get your gaping tool and gap your plugs at .035, use a bit of anti-seize on the threads of the plug and set them on your fender cover, bench  or tray.  Pick up all the tools you threw during disassembly.
If you can get them started with your hand, do so. If not you can use the extension and the socket. a piece of rubber hose or your finger tips. DO NOT start them with a ratchet. You don't want to cross thread any of the holes. Torgue is 14lbs. DO NOT OVER-tighten them. You may break the insulator.
Once you have all the plugs back in, re-install the valve covers.
I use a qtip and a slight amount of dielectric grease and and put some on the inside of the plug boot. Do not gob it, just a very thin layer inside the edge of the plug boot. Replace the wires on the plugs. Be sure that the plug wire is fully seated on the of the plug. You'll wind up with a miss if you don't. ( Ask me how I know)

Start the vehicle and make sure it runs right, there are no crossed wires. 
Now you can replace the export brace. Be sure to set the brace over all studs, and then put the four bolts back through at the firewall before you start final reassembly.

This job could cause a shy bald Buddhist to plot a mass murder.. However, if you start to struggle, don't get angry, you'll only make it worse. Walk away for a few minutes, and collect your thoughts. Re-focus and go back to the task.

I hope this was helpful. I run into many who aren't particularly mechanically inclined. It's a job, but it's not that hard with the right tools and a bit of patience.
                                                                                       -Keith

[Wedgeman]

You are making it way too hard.. this is all about the drivers side....loosen the master cylinder...get yourself  2 long 3/8th inch extensions with a 12 point 13/16 spark plug  socket. and a 3/8th wobbly....wrap a piece  of blue tape around around the wobbly as to stiffen it a bit..then an 1/2" drive to 3/8th adapter & a 1/2" breaker bar to loosen...remove  plugs.. put new plugs in the socket & finger tighten  them into the head .. tighten with a 3/8th ratchet...been doing this for 45 years on FE Mustangs...I would recommend you make this tool & super glue the socket, wobbly & extensions together for further spark plug changes .... ...and a long pair of needle nose pliers to remove & replace the boots !

[1967 eight barrel]

I do usually use my snap on long needle nose to pull boots. However,  tall valve covers can be difficult to get an angle on when the plugs are seized in the holes. I get mine done in less than an hour and forty five minutes with no scratches on finishes.

[propayne]

Thanks for the info guys - what would be wonderful is if someone experienced in this would shoot and post a well done instructional video to YouTube.

- Phillip

[Cobrask8]

That is the same method I used when changing the plugs on my 69 428 car. 4-sp, power brakes. Had the Aluminum Valve covers, driver's side rear access is flat ludicrous.

I also slightly jacked the car up, and put blocks under, so the car would bend, making re-installing the brace easier. We all know our cars do flex and bend....

After three years of doing this, I converted the ignition to electronic and a bigger coil and black wires so I did not have to repeat this insanity every Spring. Not stock, but ran so much better, and spark plugs lasted.

[427heaven]

Wedgie - Is spot on... You don't have to remove half your car to install spark plugs. An assortment of extensions and swivels and small hands and a little practice and ... Walllah ready for the track or car show. If you don't have any mechanical skills, tools, patience, leave it to your mechanic.

[1967 eight barrel]

Wedgie doesn't have a 17,000 paint job obviously.  I also have about 30K in snap on tools and have 25 different extension in 3/8" drive alone. The latter three on the left do not come out easily, especially with smog or where someone over-tightened the plugs which had not been changed in years. My hands aren't bear paws. but working on a big block car with power brakes is a different animal all together. I also don't want my shock towers scratched, and I am sure there are others who are working with a perfect engine bays.  Thanks for reminding me that most are indignant shits who don't appreciate the time it takes to translate an activity and write it. I'll be sure not to do it again!

[JWH]

1967 eight barrel (Keith) - I thank you and commend you for taking the time to write out what works for you when changing the plugs on your Shelby. Your summary is very helpful to current and future owners of Big Block Shelby's and Mustangs. Back in 1976 I bought my first Shelby, a GT500KR and the method I have come up with that works best is exactly like yours, but I even go a step further in the process and completely remove the brake master cylinder so I can get my hand on the #8 plug wire and plug. I have found that removing the Export brace, valve covers and master cylinder 1) saves me time overall 2) allows me to hand thread the spark plugs back into the head which completely eliminates the chance of cross threading 3) allows me to remove and install the spark plug wire by hand so I don't pull the wire out of the boot, I don't shred the boot with a metal pair of pliers and I am certain the wire is attached to the plug as i can feel the "snap" when I push the boot on by hand 4) eliminates scraping and scratching of the shock tower paint.
         Keep posting Keith, there are many of us who benefit and appreciate the time it takes to put together a summary as you have.
Jeff

[Side-Oilers]

Great write-ups, and thanks for the additional info, everyone.

Unfortunately, not many average owners had that kind of patience, or tools, back in the day. 

Explains why more than a few of these cars had a crude hole torched in the inner fenders for direct access to the back plugs.

[TOBKOB]

I have read several threads over the years about changing plugs in a Big Block Mustang and have yet to see a trick that we used back in the day. We would use a piece of vacuum hose slipped over the end of the spark plug and use it to start the plugs. I know there are a lot of tools today that were not available to us then that probably work better but that helped back then ( Disclaimer...I haven't worked on a BB is years).   

TOB

[Side-Oilers]

Yep, I still use the vacuum hose method on my KR and other vintage cars. 

[1967 eight barrel]

1967 eight barrel (Keith) - I thank you and commend you for taking the time to write out what works for you when changing the plugs on your Shelby. Your summary is very helpful to current and future owners of Big Block Shelby's and Mustangs. Back in 1976 I bought my first Shelby, a GT500KR and the method I have come up with that works best is exactly like yours, but I even go a step further in the process and completely remove the brake master cylinder so I can get my hand on the #8 plug wire and plug. I have found that removing the Export brace, valve covers and master cylinder 1) saves me time overall 2) allows me to hand thread the spark plugs back into the head which completely eliminates the chance of cross threading 3) allows me to remove and install the spark plug wire by hand so I don't pull the wire out of the boot, I don't shred the boot with a metal pair of pliers and I am certain the wire is attached to the plug as i can feel the "snap" when I push the boot on by hand 4) eliminates scraping and scratching of the shock tower paint.
         Keep posting Keith, there are many of us who benefit and appreciate the time it takes to put together a summary as you have.
Jeff

Jeff, My issue isn't with you, but the dismissal of my attempts at layman's terms and a list of tools for shade tree types. I am an Airline pilot and work off a check list on a daily basis. Perhaps that's why it seems wordy and overly detailed. I have had my Shelby since high school and did my entire restoration and reassembly with the exception of body, paint and machine work.
I simply attempted to contribute to the community.
                                                                                   -Keith

[1967 eight barrel]

I have read several threads over the years about changing plugs in a Big Block Mustang and have yet to see a trick that we used back in the day. We would use a piece of vacuum hose slipped over the end of the spark plug and use it to start the plugs. I know there are a lot of tools today that were not available to us then that probably work better but that helped back then ( Disclaimer...I haven't worked on a BB is years).   

TOB

I did also mention hose to start them. I am relatively coordinated and my hands don't look like Paul Bunion's. I can start all but the left rear three with my finger tips. However, the threads are very clean and I chased them when the heads were built. I know a lot of older cars are on the rough side.  I am always looking for tools that simplify jobs. I am getting older and can't afford to get hurt playing with my hobbies.  No class 1 medical, no fly.   -Keith

[gt350hr]

   Three foot long 3/8ths extension ( one piece not multiple extensions stacked) plus a plug socket with built in universal.  I had all 8 plugs changed in under 40 minutes without breaking a sweat. The toughest part was making sure the wires were "snapped on" securely after the plug install . D/S is a bear , 10 minutes alone to that side just putting the wires back on. Did it more than once. Won a bet on a 390 Mustang ( full smog but steel covers) that I couldn't get the plugs out in 30 minutes.  Plugs in and out and engine started in 18 minutes BUT I guarantee you all the plug wires WEREN'T  snapped on!
    Randy

[427heaven]

Eight Barrel-   I hope what I said about changing plugs was meant in a way that there are faster better ways of doing things. Don't take it that we are all SHITS on here with our own agendas and feel like making condescending remarks about every little thing, that was not the intent. If you give a task to 10 different people they will do it 10 different ways.