Rubber Rear Main Seals - Finally, 2 new rear main seals for the Pontiac V-8. Now owners of Pontiac V-8's can enjoy the ease of installation and reduced friction of a rubber rear main seal. These seals are not a retrofit from some other engine, but designed from a clean slate using state of the art technology and the best materials. These are not available in Parts stores! RMS300 is for the 326,350,389,400 (small journal crank) and the RMS314 is for the 421,428,455(large journal crank). RMS300 3" Main seal.......$39.99 RMS314 3.25" Seal...........$39.99