[bru65]

what would cause #2&3 to foul plugs? dual plane rpm intake,235&8 work off right side of carb right? 2&3 are black 8 is a tad rich,5 is burning nice just like all the other plugs.this has to be carb related but what would do this?car runs fine,you can hear a slight miss in the exhaust while driving or just holding rpms 1500-2500,but you cant really feel it.the car ran a 12.5 this way,but that was with new plugs.i have changed dist,wires,plug brands,added an msd6al,adj valves,carb is holley 780?dbl pump-new 3-4 years ago works great but keeps fouling 2&3 what would do this its driving me nuts. anybody ever have this happen? help thanks

[goquick]

Check your jet on that side. You could have a richer jet even though it might be stamped the same. That I think is the easiest starting place. Also you may need to check your a/f screw on that side and make sure the seat in the block isn't damaged or the taper on the screw.

[bru65]

tore carb apart-cleaned everthing with carb clean and compressed air-put different jets ft&rear.put new ngk plugs in-test drive=runs great,nail it from dead stop it will burn tire into 3rd gear,put about 25 miles on,idles good,starts up with a hit of the key.thought i fixed it by cleaning carb.--pulled plugs and 2&3 were black! rest off plugs looked great.why would these 2 cylinders be rich?????this has to be carb related but what? help

[Malky]

Burning oil? Dry, sooty black or oily black?

[bru65]

dry,sooty black

[goquick]

Where is your pvc ran too?

[Kenth]

Look for worn valve guides, missing/worn O-rings/valveseals at #2 and #3 cylinders.

[bru65]

pcv is picked up from rear of carb.guides have all been replaced and has positive type seals about 4-5000mls ago. doesnt seem oily at all but im using synthetic oil,what does syn oil look like on an oil burning plug? im going to switch to 15-40 oil and try a different metering block or carb on monday.