Well almost all early engines used them. The newer thrust plate has groves that allow it to drip. My 64 273 had one, and my dads 318 in a 70 satalite did too.
Okay , the new improved thrust plate eliminates the need for the holy bolt or the dripper. Thanks for the enlightenment djwhog. As mentioned above it`s learning little things like that, that make FABO and it`s people #1.