Rookie question

[Psalm65]

But does the 401 and 425 have a different bellhousing then the 364nail

[jmos4]

Hi,

364, 401 & 425 all 3 have the same bell housing pattern

264 & 322 are the same

Regards,

[Psalm65]

Sorry i dont know how to quote your reply. But I was under the impression for some dumb reason that the 425 had a th400 on it so with that reasoning I thought they had the bunny ear pattern but it looks more like a circular pattern.
So what's the skinny?

[jmos4]

Hi again,

BOP pattern is different than a nailhead.

The 400 trans was a special pattern nailhead only, believe AMC and Rolls Royce used this trans, 64 weren't switch pitch.

Just for reference, GM had a Chevy only pattern, BOP was SBB(300, 340 & 350) and BBB (400, 430 & 455) Oldsmobile (330, 350, 400,425 & 455) Pontiac 63 or newer I believe (326, 389, 421, 350, 400, 428, 455, 301, 265?) Also Cadillac used the BOP Pattern. Nailheads were specific to themselves as stated above

Regards,

[Psalm65]

 Thank you Jim, I think I'm going to get a 61 lesabre with a 364 and dynaflow. And I want to ditch the dynaslow. Would finding a 400 with a nailhead pattern be a direct swap? And what were the 400 nailhead transmissions called?

[jmos4]

Hi,

Th400 64 or st400 65 66 Buick are similar one has a switch pitch converter or variable stall speed the other is similar to a  normal th400, Chevy or BOP internally and in operation.

AMC use th400's that had a adapter to mate a AMC pattern to a nailhead patterned trans, might be a easier core to find?

Good luck with the swap.

Regards,

[Psalm65]

Thanks a million, just so happens I have 2 switch pitches laying around but they are BOP style. Thank you

[Dr Frankenbuick]

The 364 and 401 before 1964 had a larger crank flange and used a flexplate without a ring gear since the ring gear was on the converter for the dynaflow.  You will need an adapter for the smaller ST 400 converter snout and smaller diameter of the Nailhead flexplate.  You will need a Nailhead 64-66 ST400 or ST300 Nailhead flexplate. The old flange will need to be removed from the crank and the adapter tapped into the remaining hole.  It incorporates a smaller flange to support the later flexplate. Carmen Faso used to carry these from J&C parts in NY. Carmen is usually pretty good on Nailhead  prices comparatively.       

[Psalm65]

Thank you dr. Frankenbuick. That looks like a plan

[TrunkMonkey]

Ronnie.

May or may not help in your search, but "ST" as in ST300 and ST400, does not mean switch pitch.
ST stands for "Super Turbine", what Buick called their version of the Turbo Hydramatic (The ST-300 is the 2 speed, and named Jetaway in Olds, and was used in the Pontiac with no name other than "automatic".  The ST300 is not a "Powerglide".

You will hear people tell you the ST300 is a Powerglide, and that the "ST400 is a Switch Pitch.

And Buick did use both ST and TH in the 400 line in different literature.

If you FB, you can hook up with Matt Martin (Russell Martin's son of Centerville Auto) they are great nailhead folks and have tremendous knowledge and parts, or where to get parts.

:)

[Psalm65]

Well then that case I have a st and a switch pitch. The switch pitch will go In my wagon and a olds425. I ended up putting a down payment on a 61 4 door lesabre today .