You will come out way cheaper and easier in the end going with a 12v Cummins. Otherwise look at 6-8K for a wrecked Duramax to pull everything out of. You will have to pretty much trim the harness on your own, make your own mounts and body lift or raise the firewall/transmission tunnel to fit the Allison if you go that route. Off the top of my head Banks and PPE are the only ones that can build you a stand alone harness, as they do such for their marine applications, if you don't do the trimming yourself, but then you are talking really big $$. If you go the 12v route instead, rebuild the crossmember, drop it in, bolt up to nv4500 or built 4l80e if you keep the power reasonable, and roll with it for less than 1/2 the price.
