Packard Forum Index » Modification Discussion

The Sierra 727 kit has the advantage of an easy to find tranny that anyone could rebuild ,no electrics ,
No one has ever touched an ultramatic and the little tricks are evident in the threads so I don't trust the local shop to be able to get it right
With the 727 the flex plate and torque converter would be modern the kit has the linkages and the indicator plate for the colom it's 900
A cas e for a 727 is about 200 and a rebuild 1500 anywhere, the drive shaft has to be made up so 200 more it's got a reputation as a tough box people use them for drag racing ... It's the one for the small block 318 not the van or imperial
The ultramatic rebuild is 3500 at a fancy shop that would do it out here and 1500 at a regular one that didnt know enough to say no ,who then hedged when the splitting of the torque converter came up ,plus 400 for a re build kit and 200 x 2 for the bands ,if the torque converter is wasted it would be more
Pretty close call I'm after a daily driver with no show worries

WHat makes u lean more toward the 727 (no overdrive) rather than convert to the 700R4 or maybe even the 200R4 Gm transmissions (WIth overdrive)????

From way up in the bleacher seats, I agree. The 727 conversion is so 20th century. Using a newer box with overdrive....well, if your gonna upgrade from the ultramatic...then upgrade. Just my armchair comment - I have NO practical experience with either, other than one friend with the 700R4 who posts here occasionally.

Main reason, I guess, is that I am aware that there is a conversion kit for the 727. If there are other options that are better, I am willing to consider them. Shop still has the car which still has the Twin Ultramatic. The mechanic is trying to get it to come out of "park" when parked on an incline. Maybe I just need a new transmission guy!

There are three very obvious topics on locking in "Park" in this site's Service Index for 55th-56th cars.

Have you looked at the articles and shown them to your transmission guy?

As far as other options to the 727, here are photos of the 700R4 kit available from Bendtsen. Pictures of conversion and here is Bendtsen's website.

There is a "727" variant that has overdrive (not sure the model number), but I know that Jay Johnson in So Calif has successfully put one of those behind his 327 on his '53 Caribbean that he uses for touring. He used the Sierra Grove 727 adapter kit, but had to notch the x-frame a little bit because of the larger size of the OD equipped tranny.

He plans to do the same conversion on his '56 HT Caribbean as well.

I believe it's the Chrysler A-518, also known as the 46RH.

Also an article on converting the 727 to a 518:

hemmings.com/mus/stories/2006/07/01/hmn_feature15.html

Do you know if Jay handled the electrical as the Hemmings article suggests or did he do something different like a module such as KevinAZ has for his GM conversion. Seems like there is room for a lack of precision in either Hemmings approach.

Not sure what Jay did in that regards. Next time I see him I will enquire.