[Shootnride]

I have had the drain plug out of the radiator on my SPF a couple of times and if I remember correctly, it is not a tapered thread. I'm pretty sure it's a straight thread and uses a crush washer for sealing. Also, stainless steel has a real propensity for galling in aluminum. If you elect to use a SS plug I would suggest using anti-sieze on the threads.

Ted