cylinder #2&#3 rich?????
 

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

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.

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

Burning oil? Dry, sooty black or oily black?

dry,sooty black

Where is your pvc ran too?

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

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.