A few of hemi spark plug tubes are not sealing against the heads. Oil is going into the combustion chamber through the threads. The engine has a little over 500 miles on it. It has the older mopar performance aluminum heads. It has mopar performance wrinkle black valve covers and spark plug tubes. I installed the blue anodized spark plug tube seals that I bought from a guy on eBay. I tried removing the washers from the spark plug and it helped a little. I think my spark plug tube o-rings may be too thick and not allowing the tubes to make good contact with the heads. Plus the tubes are really hard to get out. Does anyone have a parker number for o-rings that fit better? I also think that the mopar performance spark plug tubes may not have a good enough surface for the o-ring sleeves to seal against. Do the billet spark plug tubes seal better?

you may have distorted the end of the tube when you torqued down the plugs with the compression washer on the sparkplug,...remove the tubes and inspect the ends to see if they may have nippled in shape, if so, massage back into shape with a body hammer gently, don't over torque the plugs, and do not use the compression washers on the plugs

Thanks rtscuda, I will give that a try.

Can you use these with your heads?
Milodon 27500 - Milodon Spark Plug Tube Seals

Have the heads or block been milled before ?? If so are you sure your sealing good at the intake surface ?
Is end rails of the intake bottoming out ?
If it is it will pull oil by the gasket from the lifter valley if not sealed good.

Just thoughts to check out.

Logan426

Snoopy, my spark plug tube bushings look like that, but I bought them off ebay. They are not the milodon brand. Logan426 its possible the intake in sucking oil. The end gaskets don't bottom out. The heads haven't been milled. I don't think the intake has, but I bought it used so I don't know. I pulled the carbs and didn't see any leaks by the intake ports. The intake seeps a little oil from the corner of the one of the end seals on long drives. When I pulled one of the plugs the threads were completely soaked in unburned oil. I don't think an intake leak can do that.

Thanks Mike. I just looked at one of the leaking tubes and it doesn't look perfectly round. There is a small flat on the tube, probably from storage/shipping. It's probably not a good enough surface for the o-rings to seal against. The sealing surface, but based on the marks it looks like its brinelling on the side of the cone rather than the flat face. Maybe its too wide for the head? Only 2 or 3 cylinders are leaking and their spark plugs look dirtier. They are covered in a black soot and the dry cylinders look tan. It could be the carburetors running too rich. I will find out this weekend when I start tuning them.