I am planing to swap a 4bt into my 90 F150 2wd AOD. I have heard that the AOD wont hold up to the 4bt so I was thinking of a ZF. However the local junk yard wants $750 for a ZF5 and then I would have to find an adapter. Have any of you kept the T-19 out of the step van? This sounds easier to me. What are the pros-cons of the two?