Spark plugs & wires, 72 LT-1

[Gary S.]

As long as plugs are out, I might as well replace wires and plugs. With judging/originality not part of the equation, what plugs and wires do you like for a 1972 bone stock LT-1? A search here points out spiral wound, non-carbon core, and others. I currently have AC 44 plugs and Delco 508N wires on the car. Are there more modern equivalents out there that are not red/green/pink or other ugly wires that look good? I know that, no matter what, I am stepping up to AC 45 equivalents or greater.

added:

Here is a cross reference list that I have used https://www.sparkplug-crossreference.com/convert/AC_DELCO/45 so the question is "which modern plug is good/better/best as a suitable replacement for the AC 45 for normal and sensible driving?

[Patrick H.]

Re: Spark plugs & wires, 72 LT-1

I buy my AC 45s and my ACDelco 508N wires from Amazon. 2 days and I can put them on the car.
One of the 8 wires is a bit longer than the originals, but if you install them in the correct routing you'll not notice it.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

I buy my AC 45s and my ACDelco 508N wires from Amazon. 2 days and I can put them on the car.
One of the 8 wires is a bit longer than the originals, but if you install them in the correct routing you'll not notice it.

I can find the 508N wires without issue, even at the FLAP store, and almost as easy are finding plugs. What I was hoping to hear was others experience on more modern plugs and different wires. I read Chuck Gongloff's report on wires and NGK plugs.

Gary

[Dave S.]

Re: Spark plugs & wires, 72 LT-1

I can from the 508N wires without issue, even at the FLAP store, and almost as easy are finding plugs. What I was hoping to hear was others experience on more modern plugs and different wires. I read Chuck Gongloff's report on wires and NGK plugs.

Gary

Gary,
Your heads require tapered seat plugs which will have a T designation. My recommendation would be to use AC R44T or R45T which is one heat range hotter. You can also consider TS plugs which are Tapered seat with an extended tip. I'm a fan of the old style made in USA Delco spark plugs. Readily available on EBay.

[Larry M.]

Re: Spark plugs & wires, 72 LT-1

I have R45T plugs in our 1972 LT-1. I put them in in July, 2014, and had to go to three different stores to get a set of 8 (2 from one, 2 from another, and 4 from the last). I remember when stores stocked cases of them. I figure with conservatively 20,000 miles of life expected on them, I'll never need to change those plugs again.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

Dave,
I was aware of the tapered seats but it is always nice to confirm things like that.

Does anyone know of the Denso or NGK equivalent to the R45T? A year ago Duke posted https://www.forums.ncrs.org/showthre...ke+spark+plugs citing both Denso 14U and NGK B4 both of which have flat seats. There seems to be a fair number of you that like the NGK B4 so you must have engines requiring flat seats with the washer?

[Joe L.]

Re: Spark plugs & wires, 72 LT-1

I can find the 508N wires without issue, even at the FLAP store, and almost as easy are finding plugs. What I was hoping to hear was others experience on more modern plugs and different wires. I read Chuck Gongloff's report on wires and NGK plugs.

Gary

Gary------


One of these days the Delco 508N wire set will no longer be available. Then, everyone will want them.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

Gary------


One of these days the Delco 508N wire set will no longer be available. Then, everyone will want them.

Yes, as always, we know that products go out of stock from manufacturing. Oth, the 9508n version is available although I do not know the difference between it and the original 508n. Better technology? Construction? Materials?

[Mark E.]

Re: Spark plugs & wires, 72 LT-1

508N cables, like other suppression-core cables, have fiberglass string cores impregnated with carbon as a conductor. Resistance per unit length varies when new and grows with age, heat and handling. So expect significant voltage variation cylinder to cylinder right out of the box that gets worse with time. If you use suppression core cables, it's a good idea to measure their resistance before installing. New but bad cables are not unusual.

Packard 440 is solid wire that's widely used. It works well if used with resistor plugs but can cause RFI and inductive cross-firing from the electrical field produced by an adjacent cable. I've never had RFI problems using solid core wires in steel cars and haven't tried it in a Corvette. However, cross-firing is a real problem.

In the 1990s I switched to a better technology: spiral-core cables. They offer consistent voltage drop, are less easily damaged, and create virtually no RFI or cross-firing. They're available from several companies including Accel, Taylor, Moroso, Pertronix. If you want subtle, black is usually offered but all cables I've seen are 8mm or larger. I've installed 8mm spiral-core cables in small block and big block Corvettes- they fit in the stock looms and look stock to the casual eye. For big blocks, Taylor offers a braided steel jacket over their 8mm black "Spiro-Core" wires which sport an original look yet perform much better than reproduction cables.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

Mark,
First I misspoke when I said Delco 508N wires are available everywhere. It turns out that the replacement is readily available - part is 9508N which, although I am not certain, I think are spiral core.

Regardless I ordered some "Retro" wires from Summit Racing, 7mm, all black and spiral core. I get them tomorrow so we will see.
Gary

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

I am still looking for an over-the-counter equivalent for the AC Delco 45T that gets good reviews. I bought a set of 45Ts on ebay and then a few minutes ago received a notice that the items is somehow missing from the ebay seller. Duke and others have mentioned NGK B4 and Denso 14u but those are listed as flat seat and not tapered.

Any success with the extended tip 45ts in this application?

[Mark E.]

Re: Spark plugs & wires, 72 LT-1

Try this: https://www.sparkplug-crossreference...DELCO/R45TS%20

Let us know how the Summit spiral core wires work out.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

Mark,
That cross reference was the very first place I turned to. However, they give multiple examples for many manufacturers and I was looking for real world experience from members here. Similar to the AC Delco 44/45 debate. I have several examples in each manufacturer but have no background other than my modern cars. 7 Denso comparables, 4 NGK's. Thus the question.

[Owen L.]

Re: Spark plugs & wires, 72 LT-1

Let us know how the Summit spiral core wires work out.

I bought these for my 427 and 454 cars: https://www.summitracing.com/parts/sum-g828b

I didn't want to replace the entire braided set with repros as I've read poor reviews on them plus didn't want to spend $325+ on spark plug wires for the two cars. I kept the original braided sheaths and snaked the new wires through - no problems. The wires are marked "Packard" with plenty of length to custom fit to the routing and distributor connectors / boots for a multitude of distributor cap configurations. They even come with a crimping tool that I found to work pretty well.

[Gary S.]

Re: Spark plugs & wires, 72 LT-1

That's exactly what I ordered - arriving today. Bought Ac R45T plugs but still looking at others.

Thank you for the input