So, I have been reading up a bit on different diesel conversions and thought I would start a thread on the subject. My 1970 FJ40 has an GM 5.7L, is mated to an SM465 and 3spd. Transfer case, runs ok, does great on the trail but, I am not thrilled with the gas mileage and subsequently the range even when I have 36 gallons of fuel capacity. I have been looking into diesel conversions not only for the mileage but the longevity of the motor and potential of using bio-fuel. I have read many posts about the "B" series Toyota motors and have come to the conclusion that price and parts availability is the biggest drawback to this choice. The Cummins 4BT seems like a good choice, good price and parts seem very available, I am not sure that they will have the necessary power but maybe. The last but not least is the MB OM617 (300TD) like Justin put into one of his customers. Very available at a good price, parts are also very available; the motor puts out good power and will run for a very long time. Many people have converted these motors to bio-fuel as well. The other thing I like is that Luke over at 4x4 Labs makes an adaptor plate to bolt up to a GM transmission like my SM465. Luke also states on his site that I can reuse fuel tanks and lines in place. In conclusion, I am thinking that this conversion could run somewhere around $2500.00 with me doing all my own fabrication and setup, I would double my gas mileage and the motor will last a very long time. At the price of fuel these days I think this may be a good way to go. Any thoughts?