Ok here is the deal. I have an 85 GS with a 12a that runs pretty decent, is carbeurated. I also have a 84 GSL-SE that has a 13b, fuel injected, tons of add-ons and stuff but the motor(the rotor itself) is broke or separated, I am not really sure since I just got the car last night! What I am wondering is how the parts from the 13 will fit on the 12a, if at all. Are they pretty much interchangeable or will I have to find another 13b housing to keep all the mods? This might be a newbie question but I will be the first to admit that Haynes and chiltons suck in explanation, at least to me they do. I hope someone with some knowledge will correspond with me on this either in this thread of send me a private message please! I really want to get one or both of these on the road soon! Thanks

I hear they are not interchangeable at all so I am also wondering if anyone in Illinois would have a 13b, just a decent one, that I could possibly trade my 12a for. I am not looking for anything special just something to be able to get on the road again.

 

oh boy where to start....

pretty much everything is interchangeable between the 2 cars, if I where you I would do the suspension swap so you don't have to get the bracket from racing beat (did it myself) the motor sounds like you'll need a new rotor and a rebuild, or a new engine. The parts from a fc, on the other hand, are not very interchangeable as fb parts and will need a little welding to get them to fit. I myself have done the suspension swap and am currently finishing a 12a to 13b (-se engine) swap, and the major thing i have to complain about is how the fuel lines come out is a minor pain, mostly everything else went in without a major fuss. good luck

<l><l>

 

Ok, are you asking whether you can interchange parts from a 12a to a 13b or viseversa?
Only the front cover, front, intermediate and rear cast plates, oil pump and other minor parts can crossover. The rotor housing are different sizes; 12a =70mm, 13b=80mm in width. You will need a replacement housing if one of yours is bad. If you are new to these motors I would have a core built for you and learn the rest by transfering the accessories from the bad 13b to the new core. Just my 2 cents
Good luck!

 

I have a 85 that has the 12a in it and the motor seems like it is in decent shape, just needs tuned. The other car, the 84, is the one with the 13b in it with the screwed rotor. I am asking if i can basically take the 13b out and put the 12a in the 84 and what mods I will have to do and what parts are interchangeable. Or if that seems to be too difficult then I am looking for a decent, workable 13b housing that I can buy cheap or trade my 85 for.