P1211G46 Seal Kit, Gearbox Cover: $17.50
Fits TR4, 4A, 250, 6.
Closed cell oil-resistant foam gaskets.
Includes: One length of THIN gasket for tunnel and firewall arches, and One length of THICK gasket for sealing to floorpans.
This is not as nice as the original OEM molded foam pieces, but this is the best (only) one we find out there. We buy it from The Roadster Factory.