lookforjoe
True Classic
I removed the rubber and replaced with polyurethane 90. I also replaced the rod with a tube welded 20mm lower than stock to fit my UT engine. Making a mold is not necessary. I used clay in the bottom to keep it sealed, and the center tubes in position, then poured the polyurethane. It is a good idea to use a vacuum pump to remove all air from the poly mixture before pouring to avoid air bubbles.
Will be interesting to see how well it holds up - with the rod off the centerline I expect it will alter the load characteristics - however since you used a solid fill perhaps it makes no difference?