After reading into the topic a little, I've come across a number of increases to the Saturn V's LEO and TLI performance over the course of the Apollo program. Early moon missions sent between 133t and 137t to 185km parking orbits, and could then throw about 47t to the moon. Later missions (Apollo 15, 16 and 17) orbited 140t to 141t at 167km, and each sent around 48.6t to the moon. These later Saturns were slightly uprated compared to those of earlier flights.
So, had the SA-514 and SA-515 Apollo Saturn Vs been improved a little further for the later planned missions (Which were, of course, cancelled), how much mass would they have been able to send to 167km LEO and to the moon?
Also, could these LEO and TLI masses be increased by lowering the earth parking orbit to 150km? (This would depend on whether S-IVB hydrogen venting could overcome atmospheric drag during the time before the TLI burn...)