zyewdall,do you have the specs for the 4d55t? I noticed looking up some info on the 2.5 liter version it had the same bore as the 2.6 l gasser. I think the block is the same for all three. I could not find any more info such as stroke rod hole sizes etc. i have a 2.6 in my d-50 and would like to see about converting it to diesel.