'60 401 Nailhead into '66 Wildcat with Turbo 400

[duly34]

This is what I have: 1966 Buick Wildcat Custom with a bad 401 Nailhead. I have taken the motor and trans out and will be getting the turbo 400 rebuilt. I was able to buy a low mile rebuilt 401 Nailhead with block casting number 1185484 ('59-'60 Nailhead) hoping at best it would be a direct swap and at worst I could use the good parts to go into my '66 block. Is any of this possible? I have read that the cranks in some years are different and will not bolt to turbo 400s. I am trying to learn hard and fast about Buicks, but I need some help with this.

Thanks,
Duly

[roadrunnernz]

This is what I have: 1966 Buick Wildcat Custom with a bad 401 Nailhead. I have taken the motor and trans out and will be getting the turbo 400 rebuilt. I was able to buy a low mile rebuilt 401 Nailhead with block casting number 1185484 ('59-'60 Nailhead) hoping at best it would be a direct swap and at worst I could use the good parts to go into my '66 block. Is any of this possible? I have read that the cranks in some years are different and will not bolt to turbo 400s. I am trying to learn hard and fast about Buicks, but I need some help with this.

Thanks,
Duly

The cranks ARE different. 59-63 Nailhead will have a Dynaflow crank and requires a spacer, available from http://centervilleautorepair.com/transadaptors.
I needed one of these to put a 66 ST400 on my 63 401.