425 nailhead to switch pitch trans

G

Grhopperass

Member
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.
 
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.


Sent from my iPhone using Tapatalk
 
Dr. Frankenbuick said:
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.


Sent from my iPhone using Tapatalk
Click to expand...
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.
 
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.


Sent from my iPhone using Tapatalk
 
Dr. Frankenbuick said:
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.


Sent from my iPhone using Tapatalk
Click to expand...

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.
 
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.
 
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.
 
switch pitch Tranny

nailheadnut said:
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.
Click to expand...

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.
 
Switch Pitch Torque Converter

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.
 
I think that was a switch pitch ST300 trans in the F85. The converter will fit, but will have a higher stall in your ST400. The other issue is that you don't know how the condition of it or if it works . Your best bet for is to find a rebuilt 13" ST400 converter.


Sent from my iPhone using Tapatalk
 
If it's the same part number as the converter that was in the 401 powered GS cars then it should fit. It's the same transmission within a different case. The smaller converter behind a big block will have a much higher stall than the larger diameter converter would. You should be able to go into a reputable transmission shop and purchase a rebuilt converter over the counter.
 
Dr. Frankenbuick said:
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.


Sent from my iPhone using Tapatalk
Click to expand...

The tranny fits the engine block OK. I was wondering if the torque converter will fit the crank without a special bushing.
 
I need help on this as well

I'm planning on dropping a 63 401 in where the the 300 was in my 66 skylark.

I have a 401 motor and 400 tranny out of a 65 riviera ( complete and still bolted together) that I was going to take my time and rebuild. As fate would have it, I picked up a rebuilt and running complete 401 out of a 63 riviera, and would like to use the 400 tranny w the 63 motor. Do I have to take the motor to a machine shop for the bigger bushing? or is it something that I can do at home? and will the larger bushing and adapter plate be all I need to acquire to make the combo work?
 
The 12" converter will work on the 400 without mods. Would be best to send it to Jim Wiess at TSP for a PROPER rebuild. He is the ONLY ONE in the country who does them correctly. You will need to drill 3 holes in your flexplate to fit the 12" converter as it has the smaller diameter mountings.



The rear flange needs to be ground off the rear of the crank & the bushing inserted along with the CORRECT flexplate. Make sure to line up the pilot hole in the crank & flexplate or you will end up with an unbalance condition.


Tom T.
 
You must log in or register to reply here.
Back
Top