65 st400 hookup to 65 425

[Hamel]

I need to know if there is any secrets I need to know when hooking up a 1965 st400 transmission to a 1965 425 nailhead? like flex plate position to crank? torque converter position to flex plate? bolt torque specs for both? Finally should the transmission butt up to the block with no resistance or should the torque converter put resistance against the flex plate when tightening?

[bigirish2]

There is a small index hole in the flex plate and it needs to be aligned with the small dimple in the crank flange. Not real obvious until you see it the first time. The flex plate will bolt on 6 ways so the alignment info is critical.
There should be no pressure against the converter when installed, Should be able to slide the converter back into the trans away from the flex plate a little bit. I don't believe there are any converter to flex plate issues to consider. One thing about the Switch pitch is that it is sometimes difficult to get the converter to seat all the way into the pump. If you have no clearance between the converter and the flex plate with the transmission in place, then the converter is not seated correctly.
I am assuming you do have the switch pitch converter? Best for your application is the 12 inch converter that came with the ST 300 in GS's.
Jim Weise in Minnesota is the guru when it comes to build very nice converters for Buick's.
The electrical hook up for the switch pitch is the horizontal blade on the transmission and the kick down is the vertical blade.
Mike

[Hamel]

Hi Mike, Thanks for the info. After sendind this question, I found out exactly what you stated. I tore them apart and mad the corrections and every thing fit perfectly. Thanks for your time and knowledge. Mike