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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
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| | | | Joined: Mar 2019 Posts: 1,003 'Bolter | | 'Bolter Joined: Mar 2019 Posts: 1,003 | My application is 1963 GMC 305e motor. What sparkplugs are required and available for this motor? Resistor or nonresistor type? Or does it matter? Any help is appreciated. Not finding a clear answer anywhere.. | | | | | Joined: Aug 2018 Posts: 351 'Bolter | | 'Bolter Joined: Aug 2018 Posts: 351 | The '66 AC Spark Plug Catalog shows spark plug 45NS as correct for the 305E engine. That crosses to the AC R45XLS, available currently. Both are 3/4" reach plugs. The original 45NS was partially threaded, and the R45XLS is fully threaded on the reach. Shouldn't matter, nor should the fact that it is a resistor plug. If originality is any concern, NOS 45NS plugs pop up on eBay occasionally.
Doug | | | | | Joined: Mar 2019 Posts: 1,003 'Bolter | | 'Bolter Joined: Mar 2019 Posts: 1,003 | Thanks. But all i can find is " ac r44xls" locally. Or a champion "r n12yc". Would you use either of these? | | | | | Joined: Apr 2005 Posts: 2,097 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 2,097 | The "44" series is a colder plug. It's better to stay with the correct heat range.
Fred
1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine
| | | | | Joined: Aug 2018 Posts: 351 'Bolter | | 'Bolter Joined: Aug 2018 Posts: 351 | RockAuto has 'em on close-out sale at $0.71 each: R45XLS. FWIW, I usually hold off on ordering from RockAuto until I have enough that the shipping doesn't outweigh their low prices. But, plugs are light so might be a good deal even with shipping cost, since the price is certainly right. They are good about shipping fast, too. Doug | | | | | Joined: Mar 2019 Posts: 1,003 'Bolter | | 'Bolter Joined: Mar 2019 Posts: 1,003 | Thanks guys. I went ahead with the 44s. I realize theyre a step down but will see what if anything happens. Also figured while i was in tuneup mode , id adjust valves. I should've took a pic. Not one spec of sludge and the vavle springs were still nicely painted grey. Couldnt believe it if i didnt see it myself. Oh and a tick quited down a bunch after servicing them.. Im a happy camper to say the least, so i thought id share. Have a great weekend 😀 | | | | | Joined: Mar 2019 Posts: 1,003 'Bolter | | 'Bolter Joined: Mar 2019 Posts: 1,003 | Hey Drdoug, appreciate the rockauto heads up and figured id grab them for future use. But the number of plugs available is only 1.  | | | | | Joined: Aug 2018 Posts: 351 'Bolter | | 'Bolter Joined: Aug 2018 Posts: 351 | Ha! that wouldn't be too good. Sorry about that, but, all you had to do was change the drop down to their regular inventory in the little box in the middle of the part entry, and they have them in stock at $1.40. Guess I should've explained better... | | | | | Joined: Aug 2018 Posts: 351 'Bolter | | 'Bolter Joined: Aug 2018 Posts: 351 | Ha! that wouldn't be too good. Sorry about that, but, all you had to do was change the drop down to their regular inventory in the little box in the middle of the part entry, and they have them in stock at $1.40. Guess I should've explained better...
Doug | | | | | Joined: Mar 2019 Posts: 1,003 'Bolter | | 'Bolter Joined: Mar 2019 Posts: 1,003 | Lol. No biggie. At least i know what im after next time around. It was NOT your explanation, it was probably the recipient, me, ha and or the rockauto website that didnt offer em up when clicked on. Why would there be 1 on sale and others at regular price.? Thanks again for your time and effort. Much appreciated. | | |
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