401 and trans year i.d. & info

[brad54]

A friend of mine just gave me a 401 and the accompanying trans. Not knowing anything about Nailheads past 1956 (and precious little about those either!), could someone tell me how to decode the year of the block and what casting numbers I should be looking for (is it as easy as those big ones on the sides of the cylinder heads? Or that one on the water cross over? Probably not, but thought I'd take a shot)<BR>What auto trannies were found behind 401's and how can I identify mine? It's got a real, real short tailshaft, and the trans mount is located on it.<BR>He was under the impression it might have been the Buick version of the Turbo 400, but didn't know for sure. If that's the case, are the tail shafts the same?<BR>Any and all help is greatly appreciated!<BR>-Brad

[Guest]

Nailhead engine codes appear on the passenger side valley pan rail as 2 letters & 4 numbers. 1st letter is year code, F: 1959, G: 60, H: 61, I: 62, J: 63, K: 64. The 2nd letter is the engine CI code- T: 401, W: 425, X: 425 dual quad. Afraid that's all I can shed light on here.

[Guest]

Unregistered info is different than what I have from Motor's manual. The letter id is correct for year, but the engine id is upside down (when viewed from from front of engine)on the passenger. It can be either a number/letter or 2 letters depending on the engine. '60-'62 used a number and 63-66used double letter. Suggest check the library for a Motor or Chilton or get back to me when you have the number and I will try and identify. The Turbohydro has a metal plate on the passenger side with some letters and numbers, like 64BJ is a 64 401 with column shift. Good luck.<BR>Ed

[brad54]

I've got a whole library of vintage Motor's Manuals, but as luck would have it, the only one I'm missing covers '59-'64. (Every other year, from '35 to '87, but that one's eluded me!)<BR>I've got the Chilton's manual, but it's not much help.<BR>Were there two different transmissions available? The previous owner thought it might be a '61 engine, but didn't remember for sure.<BR>Would the trans pan be the same as later Turbo 400s? It's a sinlge 4-bbl engine. <BR>Also, what's the deal with the bellhousing extensions on the blocks? I've read on here that the bell housing mount on 401s changed at one point. What was the difference, when did it occur, and can I tell what it was without the torque converter and flex plate?<BR>Oh yeah, will finding a torque converter be a problem? Are they application (Buick) specific for these engines?<BR>Thanks,<BR>-Brads

[Guest]

If it is a '61 trans then it would be a Dynaflow and the ring gear would be part of the converter. If the flexplate on the engine (it sounds like the engine and trans are separated) has no teeth then it is prior to '64, using a Dynaflow.<BR>Don't know about the bellhousing comments. I have heard them also. It is my understanding that the bellhousing is the same for 57-64 but the crank is different for the non turbohydro engines.<BR>I don't know if converters are Buick specific unless it is a Dynaflow, then they would be.

[Guest]

cant comment on the engine id numbers, but i can say that the st400 tranny should be easy to identify. it will have the same pan shape as any other th400, but it will have a shoe-heel shaped protrusion and a couple indentions in the pan. it should also be switch pitch, and have an electrical connector on the driverside of the tranny case, with two spade connectors, one vertical and one horizontal. if you see all that stuff, then it is an st400.<P><BR>pick up ron session's book on the th400, he has good pics.

[brad54]

It has the spade connectors on the side, but I couldn't flip it over to see the pan. <BR>The only things missing were flex plate and converter--lost in a fire.<BR>On the top of the bell housing, there seems to be a small vent tube or some thing. Any ideas what this is?<BR>What year did Buick go from the Dyna to ST400?<BR>Finally, anyone know if there is an adapter plate to mount a late model GM overdrive trans (like a 700R4, 4L80, etc) behind a Nail Head?<BR>Thanks,<BR>-Brad

[Guest]

OK- now I'm not sure where I got that info I typed above (old notes)- I confused myself. Ed S. got it right (tho I can't find the engine codes in my '53-61 Motor's manual). Here's what the '59 Buick shop manual sez (paraphrased):<P>The VIN is stamped on the top surface of the crankcase, just forward of the valve lifter cover on the left (driver's) side. On the right (passenger) side is the 'production code number', stamped upsidedown when viewed from the front of the car. This number is prefaced by 4F on '59 401s and 3F on '59 364s. A 1/4" long dash after the production number indicates a .010" overbored engine.<P>Sorry if I mislead...