Talked to my transmission guy-------

The Gear Vendors is much easier to do. Only minor massaging of the driveshaft tunnel with a hammer is needed for clearance. I did a big block A-518 install in my Duster and indeed the rework of the crossmembers is extensive. The end result is very good. I'm very skeptical of all the claims about the much larger parasitic loss of the 518 over a 727 based on what I'm seeing with my car. I know there's some loss but I have been told its about a half second in the 1/4 mile. My car runs low 11s @121 with the 518 and its a pump gas no power adder 440 in a 3500# car. The combo I have should be right around 575 hp and judging by the numbers I'd say thats about what I have. The claims of the huge losses are mainly originating from a trans company that sells kits to guys with Dakota trucks to swap out the 500 and 518s for 727s or 904s.