425 nailhead to switch pitch trans

**Grhopperass** · 03-09-2016, 10:58 AM

I have a 64 buick 425 nailhead out of a Buick Riviera.
Also have a T400 Switch pitch tranny.
Do I need a crankshaft bushing required when connecting like the earlier 401 nailheads required?
Any help would be greatly appreciated.

**Dr. Frankenbuick** · 03-09-2016, 06:39 PM

We need to know if the transmission you have has the Nailhead bell housing or the BOP bell housing. The transmission will bolt right up to the 64 425 if it has the Nailhead bell housing.

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**Grhopperass** · 03-10-2016, 07:05 AM

Originally Posted by Dr. Frankenbuick

We need to know if the transmission you have has the Nailhead bell housing or the BOP bell housing. The transmission will bolt right up to the 64 425 if it has the Nailhead bell housing.

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The tranny I have is out of a buick. I got it with the engine. I did not get the torque converter , so I will need to source that. I have a 401 nailhead in my car at present with a T400 behind it. With this set up I needed a special pilot bushing. I was wondering if I will need the same pilot bushing
with my new set up.
Thanks for the help.

**Dr. Frankenbuick** · 03-10-2016, 08:32 AM

The 64-66 Nailhead crank has the correct flange and pilot hole for the Nailhead ST 400 transmission. Hopefully you have the flexplate that was with the 425. Have you made sure the trans and engine bolt up to be sure you have the Nailhead bell. There is a later bell housing for the ST 400 that will fit Buicks, but not the Nailhead. The Nailhead has a one of a kind bell housing.

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**Grhopperass** · 03-10-2016, 10:20 AM

Originally Posted by Dr. Frankenbuick

The 64-66 Nailhead crank has the correct flange and pilot hole for the Nailhead ST 400 transmission. Hopefully you have the flexplate that was with the 425. Have you made sure the trans and engine bolt up to be sure you have the Nailhead bell. There is a later bell housing for the ST 400 that will fit Buicks, but not the Nailhead. The Nailhead has a one of a kind bell housing.

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Thanks for replying. The tranny I have has the same bolt pattern as the engine. I wanted to know if I will require a special
pilot bushing for the torque converter spacing. I have the flex plate that came with engine. I assume that once I score a speed
torque converter, that all will fit okay without the need for a special pilot bushing.

**Dr. Frankenbuick** · 03-10-2016, 01:17 PM

No, they were made to work with one another after 63. The earlier engines need the adapter for the st400

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**telriv** · 03-10-2016, 01:20 PM

The '64 Riv. engine you have will either be a KW, single 4bbl. or a KX which would be a 2x4 engine. Code stamped in front of the valley cover flange on the right front of the block just in front of the valley pan. In either case you will NOT need an adapter. Adapters are required for 1963 & earlier.

Tom T.

**nailheadnut** · 03-12-2016, 07:30 PM

Just out of curiosity, what info is on the aluminum tag on the passenger's side of the transmission? There should be a date and a code BT, BS, or something similar. that will tell you what model vehicle the trans was in originally.

**Grhopperass** · 03-14-2016, 01:47 PM

Originally Posted by nailheadnut

Just out of curiosity, what info is on the aluminum tag on the passenger's side of the transmission? There should be a date and a code BT, BS, or something similar. that will tell you what model vehicle the trans was in originally.

Thanks for replying. The aluminum tag on the tranny has the following No's " BR65, above that is the No'566, and there is a number 28958.
I'm not sure of the year of this trans, but it is definitely a switch pitch. I do not have the torque converter, so I am trying to find one that will fit.
Any help would be greatly appreciated.

**Grhopperass** · 03-17-2016, 10:22 AM

I have the opportunity o purchase a 12 " switch pitch torque converter that came out of 65 Olds F85 that was equipped with a 2 speed poerglide tranny. Can anyone out there advise me if this will fit my 64 nailhead and SP400 tranny.