How do you find engine number in Mazda rx7 1994?

The rotary engines do not have any type of engine numbers or VIN on them. This is from the fact that they don't have a solid block like piston engines. It is built using several pieces and therefore each piece would have to be labeled and they didn't go through the trouble to do that.

If you are attempting to verify the engine block, you can look on the top of the engine from the driver's side (on the Left hand Drive models) and the will be a 13B or similar stamped on the housings.