i was looking for the 19/32. i think i tried a 37/64 in the last block and it was too loose to stay put. i guess i could alway's just run a ream through the hole and step up in size just slightly. thanks for the info.
Andy made it sound like the 19/32 were plentiful. i was hoping he would share his source. that might make things easier for people.

i am also a believer in running the plug as an orifice, instead of completely blocking it off. it sends more pressure where it's needed during start-up and then fills the lifter gallery for some lubrication there too.