SAAC Forum

The Cars => 1969-1970 Shelby GT350/500 => Topic started by: tahart on October 30, 2022, 09:02:37 PM

Title: 1970 GT500 Spark Plug Removal
Post by: tahart on October 30, 2022, 09:02:37 PM
Before I get started changing the plugs, can anyone give me tips on how they have done it? I've read everything from swivel sockets, 3' extensions, rubber hoses, needing small hands, standing on your head, etc, etc. Can somebody that's done this condense the procedure into useful steps? My car is a '70 GT500. Tks.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: Bill on October 30, 2022, 10:23:19 PM
Quote from: tahart on October 30, 2022, 09:02:37 PM
Before I get started changing the plugs, can anyone give me tips on how they have done it? I've read everything from swivel sockets, 3' extensions, rubber hoses, needing small hands, standing on your head, etc, etc. Can somebody that's done this condense the procedure into useful steps? My car is a '70 GT500. Tks.

New School-quality 3/8th ratchet-Craftsman will do nicely
New school-3/8th drive 8-10" flexible extension (these are fantastic)
3/8th drive 5/8" spark plug socket

Old school-3/8th drive stubby, swivel head snap on ratchet-part # FKF80A
Old school-3/8th drive universal swivel
3/8th drive 5/8" spark plug socket

With these items, you can actually swap out all 8 spark plugs without removing the valve covers.

However, removing the valve covers makes the job much easier.

Bill S.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: 6s1802 on October 31, 2022, 01:04:53 AM
Or, just drive G.T.350's problem solved.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: TA Coupe on October 31, 2022, 01:27:04 AM
Take 2 days to do it so you don't get to frustrated. Have cold beer and or whiskey near by. Play some good rock music also.

          Roy
Title: Re: 1970 GT500 Spark Plug Removal
Post by: pbf777 on October 31, 2022, 11:38:17 AM
   
Quote from: Bill on October 30, 2022, 10:23:19 PM
................, you can actually swap out all 8 spark plugs without removing the valve covers.

However, removing the valve covers makes the job much easier.


     This is true, but particularly if you have the tall aluminum covers, just take'em off!   ;)    It will make the job much easier, far less frustrating, and actually turns this into not such a bad event.   :)

     But, if your into challenges, and need to brush-up on your profanity vocabulary, well then...........   ::)

     Scott.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: FL SAAC on October 31, 2022, 12:00:36 PM
GT 500....sparkplugs.....take a look at these comments

https://www.saacforum.com/index.php?topic=15975.0
Title: Re: 1970 GT500 Spark Plug Removal
Post by: PR on November 01, 2022, 08:52:15 AM
I don't think a 5/8" socket is correct, I believe it's 13/16",
Title: Re: 1970 GT500 Spark Plug Removal
Post by: 427hunter on November 01, 2022, 12:01:16 PM
Do you have the smog rails on the heads ? If so it will be much easier to just remove the rails then working around them to get to the plugs, with the rails removed it's a lot more straightforward.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: Cobrask8 on November 01, 2022, 01:09:29 PM
Have fun with 7 & 8 no matter what you take off!!!

Besides valve covers off, I also jacked up the car from the middle to relax the export brace, and took that off too.

Put in a high-power ignition system, so you don't have to change them again! I did in my 428 SCJ 4-sp.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: FL SAAC on November 01, 2022, 02:34:56 PM
Quote from: Cobrask8 on November 01, 2022, 01:09:29 PM
Have fun with 7 & 8 no matter what you take off!!!

Besides valve covers off, I also jacked up the car from the middle to relax the export brace, and took that off too.

Put in a high-power ignition system, so you don't have to change them again! I did in my 428 SCJ 4-sp.


Petronix  fits inside the cap and it's inexpensive
Title: Re: 1970 GT500 Spark Plug Removal
Post by: S7MS427 on November 01, 2022, 05:54:04 PM
Quote from: FL SAAC on November 01, 2022, 02:34:56 PM
Petronix  fits inside the cap and it's inexpensive
+1.  The Igniter III is an MSD type system that fits completely under the cap.  That's what I'm using on my 427.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: TA Coupe on November 01, 2022, 08:03:11 PM
High power ignition systems will deteriorate plugs faster but you can open the gap 5 to 10 thousandths for better ignition. You can leave the gap stock and as it opens up you can leave them in longer than you could with a standard ignition due to the extra power of the high performance ignition.

         Roy
Title: Re: 1970 GT500 Spark Plug Removal
Post by: shelbymann1970 on November 12, 2022, 01:20:33 PM
Quote from: Cobrask8 on November 01, 2022, 01:09:29 PM
Have fun with 7 & 8 no matter what you take off!!!

Besides valve covers off, I also jacked up the car from the middle to relax the export brace, and took that off too.

Put in a high-power ignition system, so you don't have to change them again! I did in my 428 SCJ 4-sp.
Yes better with the valve covers off and hopefully the prior owner installed the plugs correctly like they did on my Mach1  ;) . I only changed mine because they were in the engine since...I think Dan changed them last. The ignition system still works great. The problem though is that  the tires are too slippery. They keep spinning real easy.  ;D
Title: Re: 1970 GT500 Spark Plug Removal
Post by: crossboss on November 18, 2022, 12:48:40 PM
Guys,
Back when I raced my CJs, I had the plugs removed and replaced in 20 minutes per side. Yes, with the valve covers and smog tubes in place! Don't get me wrong, it took years to perfect this technique. I used long extensions, short extensions, and swivel sockets. I 'found' the sweet spots aka the best angles to remove/replace the plugs. In my experience, the most difficult was the spark plug wire removals (without breaking the ends), and getting them refitted on the plugs. As mentioned, removing the valve covers and taking your time on this job.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: Cobrask8 on November 18, 2022, 12:56:40 PM
Gary, you are correct. Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger. Great system, something I recommend to everybody. Looks stock, much better than points and stock coil.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: shelbymann1970 on November 18, 2022, 01:01:10 PM
Quote from: Cobrask8 on November 18, 2022, 12:56:40 PM
Gary, you are correct. Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger. Great system, something I recommend to everybody. Looks stock, much better than points and stock coil.
I like the look at it is non invasive. I'm happy with the performance.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: FL SAAC on November 18, 2022, 01:03:50 PM
Quote from: Cobrask8 on November 18, 2022, 12:56:40 PM
Gary, you are correct. Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger. Great system, something I recommend to everybody. Looks stock, much better than points and stock coil.

MSD + Petronix  = Stealth and reliable
Title: Re: 1970 GT500 Spark Plug Removal
Post by: crossboss on November 18, 2022, 01:53:34 PM
Quote from: FL SAAC on November 18, 2022, 01:03:50 PM
Quote from: Cobrask8 on November 18, 2022, 12:56:40 PM
Gary, you are correct. Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger. Great system, something I recommend to everybody. Looks stock, much better than points and stock coil.

MSD + Petronix  = Stealth and reliable



Well....not really. Pertronix has had many failure issues. I prefer the Dura-Spark II set up. Its OEM, and dead nuts reliable. Another plus, IF you need replacement parts, its at any local auto parts store.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: FL SAAC on November 18, 2022, 02:13:36 PM
20+ years in a 428 on a petronix one unit....priceless  !
Title: Re: 1970 GT500 Spark Plug Removal
Post by: crossboss on November 18, 2022, 02:14:45 PM
Quote from: FL SAAC on November 18, 2022, 02:13:36 PM
20+ years in a 428 on a petronix one unit....priceless  !


Tony,
You are one of the lucky ones...
Title: Re: 1970 GT500 Spark Plug Removal
Post by: FL SAAC on November 18, 2022, 02:17:20 PM
Quote from: crossboss on November 18, 2022, 02:14:45 PM
Quote from: FL SAAC on November 18, 2022, 02:13:36 PM
20+ years in a 428 on a petronix one unit....priceless  !


Tony,
You are one of the lucky ones...

I've heard that before over and over....
Title: Re: 1970 GT500 Spark Plug Removal
Post by: TA Coupe on November 18, 2022, 04:12:35 PM
Sometimes you make your own luck by doing things the correct way which a lot of people using the pertronics didn't do.

       Roy
Title: Re: 1970 GT500 Spark Plug Removal
Post by: 427hunter on November 18, 2022, 05:19:34 PM
Quote from: crossboss on November 18, 2022, 02:14:45 PM
Quote from: FL SAAC on November 18, 2022, 02:13:36 PM
20+ years in a 428 on a petronix one unit....priceless  !


Tony,
You are one of the lucky ones...


Scott, the issues you are concerned about with pertronix were solved many years ago (resistor wire voltage), I have run pertronix on every vehicle in the fleet for over 20 years without one failure. They make a great product.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: pbf777 on November 18, 2022, 05:56:25 PM
     We have also been recommending, selling and using the Pertronix Igniter replacement product or an awfully long time with good results and minimal failures.   :)

     But, one thing you don't want to have happen is to expose them to voltages over 15-16V as that will toast 'em!  So don't blame the Pertronix Igniter for it's failure if your regulator is out of adjustment (you shouldn't be exposing the 12V battery this for any duration either!  :o) or because your applied battery charger is set to a voltage greater. (careful of the "Fast-Charge" & "Boost-Start" modes!)  ;)  But I have questioned why their product isn't designed to tolerate this as it is not so uncommon an event for one reason or another?   :-\

     Scott.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: shelbymann1970 on November 26, 2022, 08:14:38 AM
Quote from: FL SAAC on November 18, 2022, 01:03:50 PM
Quote from: Cobrask8 on November 18, 2022, 12:56:40 PM
Gary, you are correct. Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger. Great system, something I recommend to everybody. Looks stock, much better than points and stock coil.

MSD + Petronix  = Stealth and reliable
Petronix...I remember when my friend never made it to a show as his petronix fried in his CJ 69 Mach1 on the way to the show. I'm not well versed on after market ignitions but know the one on my Mach1 that Cobrask8 put in decades ago works great and the NOS points I put in my GT350 with the stock 1970 setup still works great more than 2 decades later and has never failed me. Cruising stock is fine. Want more performance then aftermarket might be the way to go.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: shelbymann1970 on November 26, 2022, 08:15:58 AM
Quote from: crossboss on November 18, 2022, 02:14:45 PM
Quote from: FL SAAC on November 18, 2022, 02:13:36 PM
20+ years in a 428 on a petronix one unit....priceless  !


Tony,
You are one of the lucky ones...
+1 I have heard too many failures over the years with Petronix but that was MANY years ago(90s). I pass by  a building with their logo on it all the time and wonder if it is them. Wixom Mi.
Title: Re: 1970 GT500 Spark Plug Removal
Post by: crossboss on November 26, 2022, 12:02:26 PM
Guys,
All I am saying is you can take a 'chance' with Pertronix. OR use a reliable, OEM, readily available set up (and parts store friendly) Ford Dura-Spark II. Its your choice. I have been using the Dura-Spark since the 1980s, and NEVER experienced a failure. My worthless two cents...
Title: Re: 1970 GT500 Spark Plug Removal
Post by: shelbymann1970 on November 27, 2022, 10:05:09 AM
Quote from: crossboss on November 26, 2022, 12:02:26 PM
Guys,
All I am saying is you can take a 'chance' with Pertronix. OR use a reliable, OEM, readily available set up (and parts store friendly) Ford Dura-Spark II. Its your choice. I have been using the Dura-Spark since the 1980s, and NEVER experienced a failure. My worthless two cents...
As Dan(Cobrask8) said about my 69 428SCJ "Under-Cap electronic, MSD Blaster II coil disguised as stock, 8mm Plain black Jacob's wires, plugs were gapped a little bigger." I bought his old car off if his ex back in the winter of 2013. I had no clue what the system was on the car when I started putting the engine bay back together. He has a great memory and when I changed the plugs out they were a larger gap(.042 I believe) than stock. All I can say is the car has hookers on it and a stock M carb now and it runs really strong with zero issues with the ignition which I think should be at least 30 years old? I would not have a problem using a petronix if needed but my points system works great on my GT350(351W). When I first started to get the car running after dropping the engine back in it wouldn't fire. A Machine repair friend from work and a big Chevy guy who has done more BBCs for people than anyone I know told me to sand/file the NOS points. Did it and the car fired right up. Always learning then and now. Thanks for your insight on other systems to use. Gary
Title: Re: 1970 GT500 Spark Plug Removal
Post by: 427hunter on November 27, 2022, 11:32:23 AM
Quote from: crossboss on November 26, 2022, 12:02:26 PM
Guys,
All I am saying is you can take a 'chance' with Pertronix. OR use a reliable, OEM, readily available set up (and parts store friendly) Ford Dura-Spark II. Its your choice. I have been using the Dura-Spark since the 1980s, and NEVER experienced a failure. My worthless two cents...


Scott, you are disregarding what people are telling you who actually use the pertronix. I know you "heard" some stories that are now almost 30 years old - you need to just let it go. If you don't like pertronix then don't use it, but those of us that actually use it have no reason to lie or steer people the wrong way. It fits under cap, mounts to the original distributor with no mods, and works perfect. The one in my 66 vette is the same pertronix that I installed in 1999!