Is there any difference?

Can any housing be used in either position?

Does the same go for all 13B's?

 

The '79-80 rotor housings have the air injection inlet in the exhaust manifold face. The ports are not centered under the exhaust ports, so there is a definite front and rear. If you mix and match, ensure that the header gasket covers up those ports.



Non thermal reactor 12As are interchangeable front to rear.

 

yep.



the 84-85 gsl-se rotor housings are NOT sided



but the 86-now rotor housings are, same reason as the 79-80 housings.