Spark plug change experience & discovery...
Thread Starter
Melting Slicks
Joined: May 2018
Posts: 2,091
Likes: 600
From: Question Government
Spark plug change experience & discovery...
I recently changed the spark plugs in my '70 Vette. Having the proper ratchet and socket swivel adaptors made it possible. I discovered there was one mismatched brand "Champion" along side of the other 7 AC Delcos. There was also one plug that appeared much older than the others, probably since it was the hardest one to access & remove. Bet it was there a looong time due to laziness 
. Anyone have an interesting plug change experience & discovery? Do tell...
. Anyone have an interesting plug change experience & discovery? Do tell...
Pro
Joined: Nov 2023
Posts: 703
Likes: 335
From: Aubrey TX
Im a Ford guy that bought a 73 Vette last November. The car has low miles on it but it sat for more than 20 years before I bought it. The wires were older than dirt so I knew the first job was all the ignition bits. I thought hey, its a SBC. These engines are legendary for running strong for decades. All my friends in HS were Chevy guys, how bad could it be? I had no clue how different it was for Vetts and I had never dealt with all that shielding before. I cursed this car for 3 days changing the plugs and wires. The dog wouldnt come near me for a week.
GM Cert Corvette Tech
Joined: Apr 2008
Posts: 2,559
Likes: 585
From: Anaheim Hills California
Im a Ford guy that bought a 73 Vette last November. The car has low miles on it but it sat for more than 20 years before I bought it. The wires were older than dirt so I knew the first job was all the ignition bits. I thought hey, its a SBC. These engines are legendary for running strong for decades. All my friends in HS were Chevy guys, how bad could it be? I had no clue how different it was for Vetts and I had never dealt with all that shielding before. I cursed this car for 3 days changing the plugs and wires. The dog wouldnt come near me for a week.
Burning Brakes
Joined: Sep 2016
Posts: 957
Likes: 447
From: Dutchess county New York
I have a friend who is the original owner of a beautiful 70 Challenger R/T. He asked for my help with some small stuff one hot day including a plug change. That 440 six pack is like looking at a friggin' oven covered in plumbing sitting in there, it's huge. I did most of them but when it came to #7 (if it's numbered like a sbc, i dunno) he told me a big long story about how it had never been out and how it couldn't be removed except from underneath and maybe lifting the engine. Virtually impossible.
When he went inside to get a couple of cold beverages I just snaked my long Abe Lincoln arm down there and swapped it out, no problem. He'd been talking about it for 50+ years ..........
When he went inside to get a couple of cold beverages I just snaked my long Abe Lincoln arm down there and swapped it out, no problem. He'd been talking about it for 50+ years ..........
Burning Brakes
Joined: Oct 2022
Posts: 1,063
Likes: 170
From: Buckeye Lake, OH
Melting Slicks
Joined: Apr 2021
Posts: 2,720
Likes: 2,165
From: Minnesota
I’ve changed the plugs on my car 3 times since owning it. First time was when I was changing over to side pipes. Very easy to do when there’s no exhaust in the way. Second time was when I was changing the cylinder heads. I went with the instructions recommendation and went with a Champion RC12YC. Seemed oddly specific, because I was only ever to find that spark plug listed for singe cylinder engines, but I managed to buy some online. Third time was recently just because I had changed my carb around from the lean running Holley. Using a spark plug cross reference site I found some NGKs at a local store for only a couple bucks a piece, runs like a top! The headers make it much easier to access the plugs, and although it’s possible to get them all from the top, it’s easier if you have the car up in the air.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Dec 2015
Posts: 3,181
Likes: 732
From: Texas City, TX Texas
Thanks a lot for dredging up a bad memory. Time for more therapy!
All kidding aside, when I install Vintage A/C, the rear plug on THAT side will be easier. Next time I mess with the brakes, the power booster is going away, THAT side will be easier too.
All kidding aside, when I install Vintage A/C, the rear plug on THAT side will be easier. Next time I mess with the brakes, the power booster is going away, THAT side will be easier too.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,140
Likes: 4,248
From: US-PNW
complain, complain, complain...
You ain't seen nothin' for changing spark plugs on a C3 like the #6 & #8 in a big block with A/C. The compressor, the a/c lines, and the air box block all access from above. From underneath, the frame, exhaust manifold, and pipe are so close together that scrapes are inevitable. I vaguely recall that removing the side grill (on a '70-'72) or going up from the bottom through the triangular splash shield hole may be necessary. Then it's no joy trying to get the boots to snap on these new plugs!
You ain't seen nothin' for changing spark plugs on a C3 like the #6 & #8 in a big block with A/C. The compressor, the a/c lines, and the air box block all access from above. From underneath, the frame, exhaust manifold, and pipe are so close together that scrapes are inevitable. I vaguely recall that removing the side grill (on a '70-'72) or going up from the bottom through the triangular splash shield hole may be necessary. Then it's no joy trying to get the boots to snap on these new plugs!
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I have a factory BB 1968 C3 with Power Brakes, Power Steering and Power Windows and Long tube Headers. My engine was built to copy the 1968 L88 engine and is using several factory L88 parts.
When I open the hood I can reach ALL 8 spark plugs from the top and a complete plug change is less than a half hour job.
Now my C4 is another story, that takes an hour plus, especially if you forgot your Anti-Seize when the steel spark plugs get screwed into an Aluminum cylinder heads. I also use Anti-Seize on spark plugs into cast iron heads and on all suspension hard ware as well.
When I open the hood I can reach ALL 8 spark plugs from the top and a complete plug change is less than a half hour job.
Now my C4 is another story, that takes an hour plus, especially if you forgot your Anti-Seize when the steel spark plugs get screwed into an Aluminum cylinder heads. I also use Anti-Seize on spark plugs into cast iron heads and on all suspension hard ware as well.
Safety Car
Joined: Dec 2012
Posts: 3,820
Likes: 1,728
From: Summerville SC
My first vette was a 1967 vert. It seemed that all I did was change the points and plugs. I drove it almost daily for about 10 years. About a third into my ownership I got tired of pulling all of that nice shiny shielding off so I put it all in a box. About 2 years later a friend and corvette mentor was restoring his 67 vert and needed to find the shielding. I told him don’t worry about it because you can have mine. i gave him all of it, down to the last wing nut. He still has the car in almost perfect condition, parked up in the front of his garage ( like our president). The last time I visited him about a year or so ago, I recalled for him how much that stuff is worth now. He just laughed and wanted to know if I wanted to go for a ride!