is there a difference in a 13a and 13b motor if so what are they

Well a 13B is a mazda rotary.

The basic difference between the G13A and the G13B is the crank stroke and therefore the swept capacity - the G13A is a 1324cc engine and the G13B is a 1298cc engine.

The G13A was released only as a SOHC, 8 valve engine, the G13B was available in both SOHC & DOHC form and both 8 & 16 valves - fueling & engine managment vary depending on the country the engine was used in.

thanks for the help  sorry about the miss use of 13b and not g13b