John, I'm sure you are safe enough with either plug. The problem with recommending the "right" plug is that there are so many variables. Of course, you need to make sure it is the right size, which they did not do at the parts counter, but finding the right heat range and other slight variations is hard. There are experts who can look at your compression ratio, cam, heads, and drive train and tell you what plug to use for street and which one for racing.
I have World Products heads on the Chevelle, and they said to use "Accel 274 or 276, AC-Delco 43TS or 44TS, or equivalent" which made it easy to at least find a plug to get started. I did get such a recommendation for my setup, and the 44TS is the result, so it must be pretty universal! For track days, I was told to use Denso ITF22 or the AC RapidFire #1 (this was 4 years ago). Unfortunately, you are like I was before that head swap. The engine, heads, and ignition don't match the car or each other, so going to a parts house is a crapshoot. I figured out the best car to use (I think I used a '70s or '80s Camaro, depending on what I was looking for) and told them that is what I had. Telling them a '67 Chevelle would get me nowhere, even if their book or computer went back that far! All I can say is to find the closest setup to what you have and tell them that is what you have. Use what you have now, and pull them after a bit and check them out. Compare them to the pictures here http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html to see if you think the heat range is good enough. Chances are you will not be able to see anything unless it is way off or you have a bad oil leak. If you have HEI, then you can gap to 0.045. Brad Waller ([EMAIL PROTECTED]) '66 Corvette | 327/dead | 4-speed | Wilwood Brakes | 245/45/16 BFG R1 '67 Chevelle | ex-SS396 | 355/700R4 | F-Body Brakes | 275/40/17 Kumho MX > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of John Nasta > Sent: Friday, July 28, 2006 1:24 PM > To: The Chevelle Mailing List > Subject: Re: [Chevelle-list] spark plugs > > I used a 1980 Camaro w/ 305 on the Delco site and it cam up as R45TS, so > that's what I got. It seems to be running much better but I only took it > around the block. Delco also says R44TS for the Monte SS. I wonder why that > would use a colder plug. My old plugs had lots of carbon on them so I > figured the hotter of the two would be better for me. > > Next it's cap & rotor time. > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Friday, July 28, 2006 3:24 PM > To: The Chevelle Mailing List > Subject: Re: [Chevelle-list] spark plugs > > My Guess would be to get plugs for a mid year1980's Chevrolet > Monte Carlo SS > and/or Luxery Sport. > Compare those to any trucks of the same model year with to > get a heat range > to your liking. > > http://www.sparkplugs.com/results_app.asp?productTypeID=1&AAIA=1419904 > ( 1985 Monte CarloSS) > > > AC Delco Standard plug---R44TS--> came straight from the Auto > Zone page > using a 1985 Monte Carlo SS 305 HP as my vehicle. > > > > >
