Projects Nailhead in a pre-war Buick

Embarking on a new project. I am planning to put a nailhead in my 40 Super with a ST400 tranny and converting to an open rear. I researched a lot of archival threads, but did not find the info I wanted, and did not get any response from a couple of PMs I sent. I want to leave the chassis and body alone as much as possible, and plan to run the original steering box. The open rear will entail GM truck arms with a 58 Edsel rear (that I understand will bolt in). Is there one engine that is better than another for this (322 vs. 401?). Exhaust manifolds? Off center the engine? etc.? I know this subject has been beat hard, but I know someone out there has done this before and can help.

 

The 55-56 322 are better than the 53(? 0Better heads, I think. If there is a difference in width of the different engines, I doubt it is much. Don't know if the SP will fit anything but a 401/425. I would avoid the 364 simply because it's not as common. Not much help from me, I'm afraid. All of the Nailheads are good, strong engines, even the 264.

 

57-61 364s, 59-63 401s, and 63 425 nailheads require a crankshaft adapter/spacer to convert to ST400 nailhead transmissions. The starter needs to be a 1964-66 type.
The rear end will also need a Panhard bar.

 

322 doesn’t bolt up to the ST400, you’d have to use an aftermarket t adapter.


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check facebook marketplace as I remember seeing a few nailheads in adds there

 

The nailhead will work great in there. I’d recommend the 401 425 version for parts availability. The st400 is a good trans. The 64 st400 is the only one that is not a switch pitch and has a one year only valve body to work with the 64 only shifters that indicate a 2 speed trans even though they are a 3 speed.

 

If you want to run an ST400 then a 401/425 is your best choice. Find a 64 to 66 full size Buick and you've got both. I bought a 65 Electra for $800.00 and drove it home. It was a one owner, but the years hadn't been good to it.

If you rebuild the nailhead, be prepared to spend some dough. I figured rings and bearings would put mine in good shape since it ran well. However, it was slap worn out. But it's all good now.