Nailhead engine head swap info needed

[ted1922]

A friend has a 322 buick engine with early 401 heads.
He was told the heads were milled down so that the intake would fit.

I read that, even know the heads can be swap from early block to late block,
you would have compression problems.

Can heads be swap from early blocks to late ?

What is the differents between the early and late heads?

Are the chambers different CC ?

[telriv]

Although the later heads can be swapped on the early engines compression would drop considerably because of the later having MUCH larger combustion chambers. 264/322 dec heights are the same as the stroke is 3.2". 364 is higher by .100" as the stroke is 3.4". 401/425 is higher by .120" over 364 or ,330" higher than 264/322 as the stroke is 3.64". The only reason the heads were milled was not for intake alignment, but to try & raise compression, which I doubt did much.


Tom T.

[telriv]

Sorry, the diff. should read .320" not .330".

[ted1922]

how different in size ( CC ) is the combustion chamber from early head to the later heads ?

and how much lost or what would be the compress ratio if you put a late head on a early block and or early head on a later block ?

if I put 401-425 heads on my 322 the compression ratio would drop, but would the compress ratio be ideal, if I put a blower or a turbo on the engine.

[bob k. mando]

can't give you a specific idea about the resulting CR but i can explain why this is going to be hard to do.

the 264 had a bore of 3.625" while the 322 had a 4.000" bore.

the 364 has a 4.125" bore.

the 401 a 4.1875" and the 425 a 4.3125" bore.

using heads designed for a 4.3125" bore on top of a 4.00" piston leaves a LOT of extra space in the combustion chamber. especially with the pop up tops that the Nail pistons have.

[MrEarl]

Just curious, what year is your friends 322?

I am not aware of a fitment problem with a 322 intake being used with the 364 and later heads. I have read that the later heads would require some drilling of the water passages in the top of the 322 block and minor machining of the water cross over to fit.. You would need to use the later head gaskets.
I am considering using 364 heads when I build a '56 322 on which will also be mounted a McCulloch Supercharger so would love to hear more input and discussion on the subject of lower compression created by such a swap and the influence of a supercharger on it.

[ted1922]

When I check the engine it was all put together and sitting on an engine stand.
I measured the intake bolts and where the vin# was stamp, show to me that it was a 322.
what year I don't no.
the heads, I went by what the cast # was,it show to be 401.
Now my understanding that the head chamber are D shape, and what I read the CC of the chambers are all different size. 322 - 105, 364 - ?, 401 & 425 - 123-125.

Can you us the same head gasket on a 322 as well as a 425 ?
Is the gasket cylinder hole the same size ?

Any nailhead engine builder ever cc a head and or cylinder for CR?

To Mr. Earl - do you have an extra blower intake setup ?

[MrEarl]

When I check the engine it was all put together and sitting on an engine stand.
I measured the intake bolts and where the vin# was stamp, show to me that it was a 322.
what year I don't no.
the heads, I went by what the cast # was,it show to be 401.
Now my understanding that the head chamber are D shape, and what I read the CC of the chambers are all different size. 322 - 105, 364 - ?, 401 & 425 - 123-125.

Can you us the same head gasket on a 322 as well as a 425 ?
Is the gasket cylinder hole the same size ?

Any nailhead engine builder ever cc a head and or cylinder for CR?

To Mr. Earl - do you have an extra blower intake setup ?

Sorry, no "extra" blower intake set up. Just bringing this back up for continued discussion.