I have done it. The frame mounts are different from the 150 to the 258. On one side (pass side), you won't have a choice as you will use the outside pair of frame holes. The drivers side, you will use the front pair of frame holes. PM me if you need more info, or post back. There are a couple of others who have done this swap.
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.
It's just a Jeep, and if you don't wheel it once in a while, it's not even that.