How can you tell if your engine is/has a nailhead? What is nailhead? Can someone explain this?

Nailheads were the first generation Buick V8s. They were dubbed Nailheads because of the small valve diameter in the head. They included: the 53-56 264 and 322, the 57-61 364, the 59-66 401 (also called a 400 in 65 and 66), and the 63-66 425. The 264 and 322 shared one head design, and the 364, 401 and 425 shared another interchangeable head design. Nailheads are identified by the distributor in the back, a water manifold between the heads in the front, a thermostat housing in the middle of water manifold, and, of course, the vertical valve covers.

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Steve B.
GSCA #2173 (1986)
67 GS 525 Stg IV
66 GS Convertible
65 GS HT
63 Riv

So does that mean that my '64 Wildcat has a 401 nailhead?

Your Wildcat could have a 401 or a 425 nailhead. 425's were available in 1964. I assume they were available in the Wildcat. Buick also had a smaller 300 V8 engine but it is not a nailhead. The 300 has the vertical valve covers, but does not share the other characteristics of a nailhead that Steve mentioned.

Michael S.

Well I know that both of my Wildcats have original 401's so I guess they are nailheads.

KT would be stamped on the passenger side of the front valley pan rail if it is a 64 401. KW would designate a 425. The numbers and letter on the driver side of the valley pan rail match the last 8 digits of the vin code of the car (found in the driver side door opening) if it is the original engine.

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Steve B.
GSCA #2173 (1986)
67 GS 525 Stg IV
66 GS Convertible
65 GS HT
63 Riv

Ok where can I find the valley pan rail and what does it look like?

Go to the Buicks.net "Shop" and look at engine identification.

Click here (http://www.buicks.net/shop/engine_ident.html) to go to "engine identification" as Bob discussed. I know some of us are a little computer challenged at times!

Steve