If you need to remain as original as possible I am sure there are other solutions. The conversion also requires a manifold vacuum port in the intake for the vacuum modulator valve. This valve controls the shifting and I merely put a brass nipple in an existing port. The original shifter worked perfect by simply shortening the shift rod. I cannot manually shift to low but this isn’t a concern for me. I had anticipated that the speedometer cable would have required modification but on a 57 it is compatible to the C4. I believe a 55 or 56 would require an adapter.
Finally I slapped the driveshaft back in. Fired it up and checked for leaks. Since this article just deals with the trans swap I won’t go into hooking the engine back up.
Difficulties along the way:
By far the biggest difficulty was lining up all the mounting points. The rear mount was modified to go as rearward as possible on the transmission requiring me to drill new holes. If I had the body off I would make a new mount point and weld it in. I was changing cylinder heads while I had the car apart. Having the heads off and out of the way made my installation much easier.
Was it worth it:
Everyone will ask “was it worth it”? Absolutely!... The change in performance and drivability is fantastic. The car drives much differently but better. I know you can drive a Fordomatic as a three speed by manually shifting it but it’s much better to just put it in drive and go….
My total cash outlay was around $1500 for the conversion alone and I did all the labor myself. You would probably look at around 20 hours labor in a professional shop.
When I started thinking about this swap I couldn’t find any information about what problems one would run into. For those interested in this swap please feel free to email me with questions or comments: email@example.com.