cool, thanks. I got it to work.
I ended up editing the boards.txt file and added a board:
....
##############################################################
pro5v328.name=Arduino CUSTOM (3V, 16 MHz) w/ ATmega328
pro5v328.upload.protocol=stk500
pro5v328.upload.maximum_size=30720
pro5v328.upload.speed=57600
pro5v328.bootloader.low_fuses=0xBF
pro5v328.bootloader.high_fuses=0xDA
pro5v328.bootloader.extended_fuses=0x05
pro5v328.bootloader.path=atmega
pro5v328.bootloader.file=ATmegaBOOT_168_atmega328.hex
pro5v328.bootloader.unlock_bits=0x3F
pro5v328.bootloader.lock_bits=0x0F
pro5v328.build.mcu=atmega328p
pro5v328.build.f_cpu=16000000L
pro5v328.build.core=arduino
I then had to reburn the bootloader selecting this new board
The Low fuse byte is what I changed from 0xFF to 0xBF (from 11111111 to 10111111)
The 6th bit is the clock output bit.