[DeTomaso] Sodium valves

[Will Kooiman]

Rob,

Most likely, the only way to tell for sure is to pull a head.  Who knows
what you have after 40+ years.

The 72 blocks have a D2AE casting number on the block.  The D2 means 1972.
 So, if it says D2AE-something, it was cast in 1972 or later.

The earlier blocks should be D0 something.  I don¹t recall the exact code,
but I don¹t think there were any with D1 (1971) casting numbers.

The earlier blocks are called D-blocks.  There is a pad on the front of
the block above and in front of the fuel pump mount.  The early blocks
have a large pad about the size of a quarter that resembles a D.  The
later blocks are called square blocks.  They have a square, about 1/2 the
size of a dime in the same location.

>From what I recall, the square and D blocks are virtually identical, so it
doesn¹t matter.  But if you have a square D2AE block, you probably have
open chamber heads.

And if you have factory adjustable rockers, you have boss heads - which
are really just closed chamber heads with adjustable rockers.

I am going from memory, so don¹t take this as gospel.




On 2/18/15, 10:55 PM, "Robert W. Garven Jr." <robertgarven at earthlink.net>
wrote:

>   Thanks to all for the info the GT4 has them and more than a few have
>   come to no good end.
>
>   I still have mine in my car but will more than likely switch to SS when
>   I get a cahnce,hoping the
>
>   351 had solid steel valves. I am confused when you say C351-4V I am
>   assuming that is the engine
>
>   designation but 4V does not mean 4 valve?  Is there an easy way to tell
>   the difference between the
>
>   two early engines on the outside?
>
>   Thanks!
>
>   Rob
>
>   Im saving all these for future reference!
>
>   On Feb 18, 2015, at 1:31 PM, B. SEIB <[1]oldwheel at shaw.ca> wrote:
>   Hi Robert
>   Sodium valves were a feature in the 375HP version of Corvette 327
>   engines
>   with fuel injection. I don't recall sodium valves being used in other
>   US
>   standard production engines. Maybe some other exotic engines did. Later
>   valve steels and technology made the risks and expense of sodium filled
>   valves obsolete in HP engines. The idea originated in aircraft piston
>   engines back around WWII, I think, and was related to trying to cool
>   exhaust
>   valves under high stress loads.
>   The 1971 Cleveland 351-4V engines in Panteras (and Mustangs,etc.) had
>   high
>   compression closed chamber (quench) heads, single point distributors,
>   small
>   square bore 600cfm 4300A carbs and 2 bolt mains. The Boss 351 was the
>   only
>   351C to get 4 bolt mains, dual point distributor and the large
>   spreadbore
>   Motorcraft 4300D carb in 1971 along with high compression CC heads.
>   Some people have said that some 1971 4V engines found there way into
>   very
>   early 72 Panteras, but probably only in early January 72 cars. The 1972
>   Cobra-jet engines would have entered production in Sept of 1971 and by
>   the
>   end of 1971, DeTomaso was likely to have used their engine stock on
>   hand and
>   have received new Cobra-jet engines from Ford. I understand DeTomaso
>   was
>   generally receiving engines only about a month or so after they were
>   produced in the US plant.
>   1972 Panteras came with Cobra-jet engines that had open chamber (lower
>   compression) 4V heads but with 4 bolt mains, dual point distributor and
>   large spreadbore Motorcraft 4300D carb. This was the strange result of
>   Ford
>   trying to recover some of the power lost to stricter emission standards
>   for
>   1972. The compression had to come down for unleaded gas and Ford upped
>   the
>   RPM to try to get some oomph back. They retarded the cam timing and
>   hopped
>   it up a bit to get the power at higher revs, thus the dual point and 4
>   bolt
>   mains.
>   1973 and 74 went downhill from there, with increasing emissions and
>   lower
>   compression.
>   So...the best heads were in 1971, but everything else was better in
>   1972.
>   Unless you have a 1971 BOSS 351 engine, which never came in a
>   production US
>   market Pantera. Pity that.
>   Barry
>
>References
>
>   1. mailto:oldwheel at shaw.ca
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