I needed to install a seal. What I did was brought the seal to a flea market and found the right size PVC coupling to install it. It isn't your ordinary PVC size, it's gray in color and measures 23/8 on the inside and 3" on the outside. It fits many seals that we encounter. I tried on a SB timing cover seal and it will do the job.
Clean the bore in the cover real good, grease the outside of the seal with axle grease, and slowly tap it in around the edges and try not to **** it as it goes in... Once it catches, tap it evenly until it's seated...