I rebuilt my Perkins 4.108 5 years ago for about 3,000. That was with me doing the rebuilding in my garage, Diesel Parts Sales doing the block work (press in new liners and cross hatch them) and head work (lap and install valves. That does not include the crane to get it out or in. I hooked it up myself and aligned it myself. Diesel Parts had a rebuilt engine (also 4.108)and tranny for sale in their showroom for 5800 dollars and that was a bargain. I chose to do the work myself to learn something abot the engine and saving 40% did not hurt either. I suspect the cost for your bigger engine would be a bit more but not much. Consider the fact that Perkins engines are so well thought of that if you repower you can get a couple thousand for one that runs to defer the cost. Check to see if that engine is sleeved like the 4.108 because if it is then new sleeves is like a new engine (at least from the combustion chamber/piston aspect). I hope I have shed some light on the other option.