thank you all for the replies...
these were installed on my 98 cobra when purchased. I have taken them off in favor of Saleen SC wheels that I am going to put street comp tires on. I was going to keep these with the Nitto 555R in the front and put either an M&H racemaster or drag radial in the back.
275 tires seem to fit just about perfect as they are a 9" wheel.
the SC is going to be a 10" rear, 9" front. I was just not sure exactly what they are. I did not think they were OE off a cobra R, as those are supposed to be the Hinodex wheels, which there are some for sale local to me for $1200 including a free car...