It might need a little length. My Spyder's wheelbase is 83.5" or so. I believe Speedsters are about the same.
An original 356 is listed on the Google as 83.75".
Henry at IM lists the wheelbase as a range from 83.8" to 86", I'm sure to accommodate either type1 or Porsche 911 chassis designs.
I'd measure the body carefully to make sure.