If you really are interested in puttin a RB motor in a 240, i would personally go with the rb25det out of a 93+ skyline gts. it puts out 250hp to the crank which is about 220 to the rear wheels and unlike many people say, it is not a very hard swap. there are many shops out there that can do it for about 7k. i am in the process of doin this swap myself and almost complete. just a little bit of wiring to do and it should be good. I fought that if u realy want to do a RB swap get the Mckinney motor mounts and driveshaft, they are a life saver because they move the motor an inch and an a half down and back. gives u better clearance, and also shifts the weight in the right direction so its not too heavy in the nose like everyone is concerned about. There really is no custom fabrication required if u get those mounts. Mckinney motor sports also has downpipes and wiring harness's that u would need for ur swap.
lilskyline240