Spark Plug Tubes Fitment Issue

[jreynolds]

Hello, I am having issues finding the correct spark plug tubes to fit a 68 road runner 426. I have tried the normal spark plug tubes and they are too short. Cannot torque the spark plug without it flaring out the bottom of the tube. From the lip on the valve cover to the spark plug hole it measures 6 1/4". I have attached a picture of the valve covers. Does anyone have any suggestions as to what tubes to purchase or something I am just missing? Thanks in advance!

 

[pnora]

Mancini Racing Tall Spark Plug Tube & Seal Set

 

[Jerry Hall]

Remember to not use the washers on the sparkplugs as they will distort the tubes, even if the tubes are the correct length.

 

[jreynolds]

Thank you! I have removed the washers from the spark plugs as well.