Time for new plugs in the L98. Took one out, AC R45ts. Went to parts store and got a set, ouch, 21 bucks. Took out the old ones, gapped and lubed the new ones, screwed them in finger tight. Could not get the socket on a couple to tighten, no way. Finally pulled a new plug out, they are about 3/8 inch longer from seat to tip than the old ones. Had to saw off the end of the socket to get it on. You've been warned folks, compare the new plugs to your old ones. And if the wire end is already close to the header it will probably be right on it with the new longer plugs.

 

I would recommend going to an NGK plug over the AC Delco. I made the switch, and the engine loves it, especially on the top end. An NGK # UR4 is stock, i would recommend going to a UR5 or UR6 (colder heat range) for anyone with power adders (headers, cam, intake, nitrous, etc) and if you want to run a platinum plug just add "gp" to the end of those numbers, ie UR6GP.

Personally I went UR6GP. If anyone is running aluminum heads, your numbers are FR4, FR5, FR6 etc....

 

i use bosch supers with me headers, because they are almost as short as the fancy header plugs for ALOT less money, they are far shorter than ac's

nothing fancy just about the cheapest pluc out there

 

When it comes to spark, no sense in cheaping out when thats a major player in your engines functionality and you don't really replace them that often. If you think about it, you might spend more money on soda in the time span lol. I use the accel shorttie spark plugs. You can even unscrew the metal tip that makes the eletrical connection to your plug wire if you need more room. Accel also has ceramic plug boots for header people. Very nice... less clerence issues, less wrench time, less melted plug wires and crispy boots... More driving!

ps, link is just for a pic reference, this might not actually be the right part for your car

http://accel.carshopinc.com/product_..._id/1304/0437S

 

Will those NGKs fit vortec heads? With the vortec heads, would it be better to use one of the UR4/5/6 or the TR55/TR55-1? I'm wanting to make the switch to NGKs but I am unsure of exactly which one to use. Any help is appreciated.

 

You can get a set of Accel shorties from Oreilly's for like $26.

I took a 5/8 deep well socket and put a short 1/4" bolt and nut thru the ratchet end so the socket basically has a 7/16 hex head on it that I can turn with a combination wrench. Works great for the tight places.

 

i use accel 276s plugs. work great for me.