1974 Coupe spark plug ??
Thread Starter
Cruising
Joined: Dec 2020
Posts: 12
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From: Lincoln. NE.
1974 Coupe spark plug ??
I recently bought a 1974 Coupe that had been sitting for a number of years, it has 350 small block with an Edelbrock Performer intake & camshaft. Am installing a new Edelbrock AVS2 1906 650 carb next week and think I should also update plugs, are AC Delco Rapidfire Performance Paltinum Series plugs a good choice or is there a better plug? This car also has headers and dual exhaust just want a reliable plug, not looking to race or anything like that.Thanks in advance for any sage wisdom passed on.
68Topless
68Topless
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From: Sunshine Coast, Queensland, Australia
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Lot's of choices. Me, I'd run standard NGK's.
Sorry, don't know the number for your engine.
It wouldn't be hard to look up.
Sorry, don't know the number for your engine.
It wouldn't be hard to look up.
Burning Brakes
Joined: Dec 2017
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2023 C3 of the Year Finalist - Modified
I prefer copper spark plugs.
copper conducts better than iridium and platinum. And significantly cheaper.
however, the iridium and platinum plugs last far longer. I use the rare metal spark plugs on engines that are a PITA to change the plugs on, so don’t have to do it often.
on most sbc’s, which are easy to change, I use copper plugs. Cheaper and better spark.
copper conducts better than iridium and platinum. And significantly cheaper.
however, the iridium and platinum plugs last far longer. I use the rare metal spark plugs on engines that are a PITA to change the plugs on, so don’t have to do it often.
on most sbc’s, which are easy to change, I use copper plugs. Cheaper and better spark.
Race Director
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From: Sunshine Coast, Queensland, Australia
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The thing is, it's not just that it's a 350 Chev.
As an example, I run a NGK BKR5E-11 plug in my 350.
With aftermarket aluminium heads that require gasketed style plugs and a very hot DUI distributor with compression a little over 10-1.
A engine with stock heads that require a tapper seat plug will definitely be different. Compression, cam and tune also affect which plug is optimal.
As an example, I run a NGK BKR5E-11 plug in my 350.
With aftermarket aluminium heads that require gasketed style plugs and a very hot DUI distributor with compression a little over 10-1.
A engine with stock heads that require a tapper seat plug will definitely be different. Compression, cam and tune also affect which plug is optimal.
Le Mans Master
Joined: Apr 2011
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From: Hermosa
UR6? I think you'll find that to be too cold, at least at stock compression. 5 is kind of the sweet spot for street driving on a modified engine in the 10:1 CR range IMO. The more mild the engine the hotter you'll want the plug to keep it clean, in the range of 4 to 6. UR4 works well with the low compression stock engine specs in my experience.
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From: US-PNW
As an aside, while the rare-metal plugs may last longer, that's kind of a non-starter with our cars. Are you really going to put 100,000 miles on the plugs to see the benefit of longer life? I doubt the plugs most of us have will ever see 30,000 miles!
1967 Pedal Car Champion
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From: US-PNW
I've never heard this aluminum vs. iron head statement before this thread. I'm of the thinking that it must not matter because in all the "what spark plug should I run" threads, folks aren't advising against one or the other depending on head material.
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Well I'm not sure where your reading. But it does make a difference, old school iron heads flow differently and have vastly different, (less efficient) combustion chambers.
even the amount of total ign. Timing varies between iron and aluminium heads.
Most stock SBC iron heads require tapper seat plugs. Most aluminium heads require a gasket seat plug.
Lot's of differences.
differences in ports, combustion chamber design, compression and even cam timing all effect plug choice.
perhaps your only reading about people with factory stock engines.
Which in the world of 40-60 year old SBC engines is less common than much newer vehicles.
even the amount of total ign. Timing varies between iron and aluminium heads.
Most stock SBC iron heads require tapper seat plugs. Most aluminium heads require a gasket seat plug.
Lot's of differences.
differences in ports, combustion chamber design, compression and even cam timing all effect plug choice.
perhaps your only reading about people with factory stock engines.
Which in the world of 40-60 year old SBC engines is less common than much newer vehicles.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,137
Likes: 4,248
From: US-PNW
Well I'm not sure where your reading. But it does make a difference, old school iron heads flow differently and have vastly different, (less efficient) combustion chambers.
even the amount of total ign. Timing varies between iron and aluminium heads.
Most stock SBC iron heads require tapper seat plugs. Most aluminium heads require a gasket seat plug.
Lot's of differences.
differences in ports, combustion chamber design, compression and even cam timing all effect plug choice.
perhaps your only reading about people with factory stock engines.
Which in the world of 40-60 year old SBC engines is less common than much newer vehicles.
even the amount of total ign. Timing varies between iron and aluminium heads.
Most stock SBC iron heads require tapper seat plugs. Most aluminium heads require a gasket seat plug.
Lot's of differences.
differences in ports, combustion chamber design, compression and even cam timing all effect plug choice.
perhaps your only reading about people with factory stock engines.
Which in the world of 40-60 year old SBC engines is less common than much newer vehicles.