Technical Calling All Dynaflow Gurus, Would ike to Compile Dynaflow Differences

I dont know if anyone has ever asked this question, I cant seem to find it. I know bell housings and designs have changed over the years, but do all Dynaflows share the same external dimensions? Im asking the question because Ive never found a 100% answer to my idea. I want to swap another Nailhead into my 55 special, Ive found 364's and 401s reasonably priced, but they use a different bell housing. Then I read that you can swap the bell from a 57 only 364 Dynaflow onto the 55 Dynaflow, then Ive heard they bell is cast into the trans and cant be swapped. Then I started thinking, they improved the Dynaflow over the years maybe a later one from whatever donor car I choose would fit. But if the Trans is longer then I have to get a shorter torque tube and god only knows whats involved in that, or if the trans mount is in a different spot etc... So I was thinking we have a lot of smart guys on this board and to help my self and everyone else maybe we can compile a list of year to year differences. It would be nice if we could just look them up like a TH350 or 400 and know all the various measurements.

 

I have very little of substance to offer, but I will contribute this....A close friend I knew for almost 60 years was a splendid Mechanic and a worked for years on Chevrolets and Buicks and rebuilt hundreds of GM automatic transmissions. He once told me that the last generation of Dynaflows, the Triple Turbine, was really a very good transmission. They were soon superseded by the ST400/TH400. I do not recall the case configuration of those TT Dynaflows, but they were installed on 401 and possibly 425 nailheads (if they were available in '63).

 

The Triple Turbine was only offered in 58 and 59. The Twin Turbine was used up to 1963.

 

My mistake in the model name...it was the later unit. Thank you for the correction.

 

I heard the Turbo 400 was ready to go in 57 but they couldn't put it into service because of copyright issues...

 

I just wish I knew what year Buick did away with the Torque tubes, and if a Triple turbine would be the same length as my twin turbine. Or if all twin turbines were the same, and you can swap bellhousings and converters between years...

 

I believe '60 models were the last of the torque tube drive lines.

 

YES

Ben

 

OK Cool now we're getting somewhere. I'm going to climb under the car and measure my trans to get the first measurements online.... I'm going to measure from the bell to tailshaft and then bell to transmount. Can you guys think of any other measurements?

 

It's been awhile since I looked at a Dynaflow...probably 10 years or so. I am thinking the bell separates from the main trans case. You might want to measure the bell length to that joint...unless I am 'mis-remembering' them as separate parts. It could be that not all versions over the years were constructed the same in that regard.

 

Info on the straight eight Dynaflows would be great also.

 

I've heard that the one from my 55 fits in a Buick with a straight 8. But I'm glad I'm not the only one interested in this. My goal is a mild custom 55 Buick but because I have a Special it's godawful slow, and has cappy miniature drums. So my goal is a bigger Nailhead engine swap, along with keeping my Dynaflow, and big drum swap. I'm going to try and get all that info on here to help others...