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4 speed 727???

Mopar Muscle
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4 speed 727???

jclaus68 jclaus68
New User | Posts: 33 | Joined: 09/09
Posted: 05/14/13
08:52 PM

Gentlemen, looking for some help here with my transmission selection.  I'm in the process of building a 500ci stroker for my 68 Charger an have made the decision that the 3 speed 727 behind the 383 I have in it now, that it that I have absolutely no history on, probably isn't a good idea to run behind the monster I'm about to drop in the K member.  At first, the obvious decision was to pull that out, rebuild it and hope that it would be able to handle the 500+ ft lbs of torque this engine is destined to make.  Then I got to thinking, I wonder if there is a 4 speed automatic out there, that isn't electronic so I don't have to reinvent the wheel trying to get it to work in an electronically antique car, AND that could stand up to the kind of power I plan to throw at it???  I've done some research and it would appear as though the bulletproof 727 transmissions where later named using a 4 character numonic that characterized what the transmission was.  The first character being a number, either a 3 or a 4, denoting 3 or 4 speeds.  The second, again a number, 1-9, denoting the torque capacity of the transmission, 1 being the lowest torque capacity, 9 being the highest.  The third, being a letter, either R, T, or A, denoting Rear, Transverse, or All wheel drive.   And finally, the fourth being a letter, either E or H, denoting a Electronic or Hydromechanically controlled transmission.  So, with that information in hand, I determined that the best choice for my high horsepower, high torque engine would be a 49RH.  A transmission that according to google, doesn't exist.  So, I searched 48RH, and got some results, mostly diesel websites advertising high capacity oil pans for these units.  But not many options for purchase of such a transmission and what I could find only had a tail housing designed for a transfer case to bolt up to it.  Again, I lowered the second number to see what came up and again, more diesel sites and transmissions with t-case tail housings.  Has anyone heard, seen or put a 4 speed, hydromechanically controlled automatic trans behind a big inch mopar?  And had good luck???  Would really appreciate any info anybody out there might have.  Thanks in advance guys.  

Cudadon Cudadon
User | Posts: 204 | Joined: 02/08
Posted: 05/15/13
12:39 PM

First you will need an Ultra Bell adapter to put a A518 or A618 to a Big Block.  A well built 46RH might do the job.  The 47RH and higher are all A618 diesel units.  They have lower shift points and may not work well with a 383.  The only 48 I know of is a 48RE.  TCI has a performance rebuild kit that might do the job in a 46RH.  You will find a lot more 46s available.  You will need to work with the hydraulics for the OD and lock up.  
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jclaus68 jclaus68
New User | Posts: 33 | Joined: 09/09
Posted: 05/15/13
06:58 PM

Thanks Don, for the trouble that it sounds like it is, I think I'll probably stick with my 727 and tach 3 grand on the freeway.  

Spud490 Spud490
User | Posts: 65 | Joined: 01/12
Posted: 06/06/13
05:23 AM

Build the 727 right and it will handle 1000 hp easily. Then if you have the $$$ use a gear vendors unit ( overdrive / under drive ).  
10's or bust!!