Yeah, quite possibly, I've found someone that has botched them onto SR20's, and I know an SR20 box can be put onto the CA (with a bit of messing) so it's looking pretty good.
I just need to get an RB box and give it a go, if I have to chop and weld a couple of bell housings togeter then so beit, certainly a cheap way to getting a strong box.
The RB25 head and block is very similar the CA.