Are the front and rear rotor housings pretty much identical or entirely different?

I picked up a good front rotor housing and rotor for cheap, and looking for an additional rear set to assemble a new keg.

My current keg blew the apex seals in the rear set out and demolished it.. The front is good, I was wondering if I could just use another front set to make a complete engine. I already scrapped the junk rear set to compare differences and similarities so now Im needing some input..

Thanks

 

They are the same, but if for a turbo engine, the rear housing has no freeze plug above the exhaust port. This port is used for coolant supply to the turbo, so if this is going into a turbo engine, make sure to remove the freeze plug.

 

but they r different between pre-86 and 86 on.

 

Ok good, I shouldve clarified more but this is an 13b S5 engine that is N/A.

I appreciate it guys. So I guess I can just get this ball rolling then and finally finish this money pit.