[DeTomaso] Sodium valves

Robert W. Garven Jr. robertgarven at earthlink.net
Wed Feb 18 22:55:02 EST 2015


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 <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


-------------- next part --------------
   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


More information about the DeTomaso mailing list