68 Polara convertible, manual swap or 4 speed auto?


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Apr 12, 2016
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Vancouver (Not BC), Washington (Not DC)
I'm toying with transmission options on my Polara. Part of me wants to keep it auto but at the same time I like having 3 pedals and gears to hammer through. The transmission that's in it is the original 727 3 speed auto, which I am pretty sure is toast as it takes 3-4000 RPM for the car to move.

One option I researched was using the later A-518, which I can get out of a V8 Dodge Ram van and install with little trouble, have to move the mount, and cut the bellhousing off and install an aftermarket big block bellhousing from Summit, as well as a few pressure switches to activate the overdrive. This would give me an extra gear, and allow me to put some slightly taller gears in the rear end (It's got 2.73 or something like that, I've decoded the fender tag but it's been a while) and still get good numbers on the highway...

Other option is I'm thinking newer 5 speed or 6 speed manual, like out of a Dodge truck or something, but I am not sure what's involved in a manual swap. I remember looking it up years ago and most of the information I found said that most of it was fairly simple, however the pedals and linkages and other junk were C-body specific and not exactly easy to find, although I thought maybe I could use a pedal box out of something else and modify it, since if I went with a 5 or 6 speed out of something newer it'd likely have a hydraulic clutch which could simplify things. Thought I'd throw this out there and see if anyone had any input :)
is there anything available for a Mopar big block in 5 speed automatics ?
I would love to see a manual set up, but I would personally rebuild the 727, probably would never have to touch it again.