Tire size ?

1988 735IL:
I now have P 205/55/R-16 that are shot
P 225/50R 16 these are new will they fit?

Yes they will fit. In fact, I believe that 225/50/16 is the stock size for a 16 inch wheel.

http://www.miata.net/garage/tirecalc.html

I punched in the sizes and this is what it returned:

"Speedometer reading with non-stick tire is 0.1% too fast.
When your speedo reads 60 mph, you are actually traveling 60.0 mpg."

Thanks very much, my 16-Year old son will be happy!