Hi 260 DET

Maybe you just got lucky. An LS conversion would have been very complicated, the M113 is they way to go. You can use the M113 with the existing auto or convert it to a 6 speed manual. It will all bolt straight in. An M113 conversion will be very similar in weight to the M112K supercharged V6 and will have a slightly lower centre of gravity. The 5.4L NA engines are getting hard to find here, so a 5.0L would probably be the quickest way forward. The best way to get extra HP out of the 5L would be some cams and a matching tune, to try and get and extra 1000 rpm out of it (it should be OK for 7000rpm). You could run it all from a stock ECU (and stock TCU if you go with the auto). I can make you a suitable ECU (and TCU if you use an auto). There's no need to change existing transmission to a V8 unit, but if you get one cheap with the engine, then that's even better.