I've had my Camaro for about 10 months now that I've only put maybe 500 miles on, and am going through spark plugs pretty quickly. I was using Champion #17 plugs which are the hottest available before going to platinums, and am now using ACDelco #44 plugs, but it seems no matter what I use they foul out (carbon deposits) after like 5 minutes. I adjusted the float levels in the carb (Holley 600) because the rear bowl wasn't even getting any fuel, and I checked the levels so it shouldn't be getting too much fuel. I guess my question is what spark plugs are you guys using on a 350 motor? I was told by the previous owner he thinks the motor was a mid to late 70's from a truck, it's not the original motor.

 

anyone? I need to know what to do or what can be wrong. Could I just buy 1 spark plug thats different until I find one that burns right so I dont have to keep buying sets of 8 every other day? I wouldn't imagine it could do any harm to my motor running 1 plug thats different from all the others. Or is there another way to lean out my carb?

 

Got pics of your plugs?

 

R45 is the stock heat range, you're a bit cool on those delcos.
Either way i'd be guessing you're either running pig rich or it's letting a lot of oil by the rings.
You choose the heat range based on the heat line on the plug. If it's getting deposits then the mixture is off, or you've got a fair bit of oil loss. Does it burn much oil?

 

Do you have a PCV valve hooked up?
If you were to run the coldest plug in a properly tuned engine that needed the hottest plug it would be weeks before it would foul out.
Some common things to check:
1.Timing way late and the idle cranked open on the carb. (like late model dizzy with no computer)
2.No thermostat or stuck open.
3.No pcv valve.
4.Choke not pulling off.
5.Carb jetted way wrong (rich), mains dripping (see #1).
6.Crimped/blocked exhaust

 

well it's not a sludgy buildup on the plugs so I know it's not oil, also 'cause it's a dry black deposit which smells like gas which I know is why it is rich, and my car doesn't burn oil at all. The guy at Autozone said Champion #17 plugs are the hottest before going platinum, but I know Campion plugs are crappy so I asked for a cross reference for AC's and he gave me the 44's. I guess I'll have to take my business to Advance where they might know a little more about plugs. What is the hottest plug for the ACDelco brand and what should it be gapped at? I currently have them gapped at .035. And yes I do have a PCV hookup, t-stat is new as with the exhaust, and I fixed the choke several months ago (electric, wasnt opening but is fixed now). I'll check timing when I throw in new plugs. Thanks for all the help...

 

49 would be the hottest.
From 41-49 is the heat range. Stock is 45.
I run 42's for what it's worth. I'm not sure if you can get 48/49.
I'd recommend a 45 or 46 if possible.

But I think first off i'd look at idle mixture and primary cruise mixture, and timing at idle. What distributor do you have? Got enough enough juice to fire off a mixture or is it an old stock style one?