razman

what spark plug are you guys running on your L36 engines? i just pulled my plugs (R44XL) and they are pretty fouled up..car has been missing a bit too. plugs are completely black, totally carboned over, but not "gunky" if that makes sense. now, granted, sense i'm still restoring this car, it hasn't actually been out driving, i broke the cam in initially by running at higher RPM for 20min ish, and then have started it and ran it occasionally for the past couple of years while working on it...it maybe has a couple of hours on engine? (i tried not to ever just leave it idle for long periods)

the original plug spec for car is 43N (hard to find) but have heard that R45XLS is a great plug to run on the street, and less likely to foul? btw, engine was built back to factory specs, and is running a quadrajet. thoughts? thanks, Rick

Ironcross

AC, R-45-XLS.....should clean up your bad cylinders if there isn`t a problem internally...and dont remove the washers off the plugs...If performance is needed set the plugs at .035 with whatever ignition system your using....Cant beat the OE stuff

capevettes

I agree with Wally. I run AC R45 XLS in my 68 427/390. I just changed them after 3 years and they still look new. 45 is the right heat range for a street driven Corvette in both big and small blocks. It may help your situation if there aren't other issues causing your problems, like carb.

Jeff_Keryk

I like cheapo Autolites...

razman

thanks guys, i picked up a set of AC R45 XLS today...we'll see how they perform! Rick