Install rubber rear main seal — special instructions

Install rubber rear main seal --- special instructions.

We pioneered the rubber crank seal in the Nailhead in 1982. The best part of using them is they can be installed with the engine in the car. I am not going to mention things that are in the factory manuals or in my seal instructions that come with the seals..  We use these in all our 364-401-425 engines we build.
Engine in car
If you are installing a new rubber rear main where a rope seal is now the hardest part will be removing the old seal in the block. Remove main cap and loosen the other main bolts, screw a small sheet metal screw into the rope seal being careful not to scratch or nick the crank, as you pull on the screw rotate the crank in that same direction. Next install one on the rubber seals in the main cap and check for fit. Shorten seal as needed, this is explained in the seal instructions that comes with the seals. Remove the new seal from the main cap and install in the block, by fitting the seal in the cap first you only have to install the upper seal once. Now check the fit in the block and fit the other seal into the cap and trim if needed again.
264-322 rubber rear main seal
This is something that may not work in all blocks, we have found variations in seal grooves machined in the blocks. Some are machined too deep so seal lips are not held tight against the crank surface. Thin strips of harder rubber maybe able to be used under the seals to tighten them up but we have not tried it. We recommend using the rope seal if the crank is out or on a rebuild. More details come with our seals.