Specifically, I want to put an RC24 engine in an RC36 frame. I believe the rear mounts on the crankcases are the same, but there's possibly some variation in the upper mounts on the heads. Seems the RC30 heads are a cross between the RC24 and the RC36, being like the 24 in design, but with 36 upper mounts. So in fact 30 and 36 engines swap relatively easily (or so I've read). However, I want to put the 24 engine in the 36 frame. Anyone done this and can point out the pitfalls or offer any tips? BTW, I'm not looking for any discussion about the sense or otherwise of doing this. Just trying to get information about it before I do it myself.