Just make sure to rotate the new FSD 90° to the direction the old one was mounted (as evidenced by the trace outline of heat compound on the underside of that sink) because it is much more thermally efficient if each transistor has its own, dedicated, set of cooling fins instead of sharing the same set side-by-side and leaving half of the cooling plate essentially unused. It also helps if you set the FSD a couple of inches back from the leading edge (closest to the source of the airstream) as far as heat dissipation goes. You will most likely have to drill and tap four new mounting holes to re-orientate the FSD, but that is fairly easy, just make sure the holes fall between the fins and not atop one. Oh, one other helpful hint. Completely clean any heat sink compound off of the sink and your FSD. Use Arctic Silver heatsink compound (the best stuff out there, used to be available at Radio Shack back in the day, can still find it on-line) smeared in a very thin layer on the back of the FSD and on the two transistors and in their wells so that it is even with the back of the FSD. This will maximize heat transfer from the FSD body and the transistors to the heatsink, as it's the two transistors that produce all the heat.