O.K. just thinking aloud here, what would be involved in swapping a 57 Olds 371 in place of a 55 324 in my 55 ? Can I still use my existing Hydro ? do the 57 engines mount the same ?? Thaught process being a running 57 might be better (like saving thousands in rebuild costs) then building the stuck 56 engine I have in the shed which is slotted to go in the 55 while the 324 comes out fro another project..... Anyone done this swap or have acess to both engines to confirm ?