<VV> Cylinder head drawings

[BobHelt at aol.com]

Hi all you drawing experts,
Recently CORSA released some original Corvair cylinder head drawings which  
were posted on VV and The Corvair Forum.
 
Among these drawings were those for two different 1965  95 hp  heads, 3856743 
and 3883862.
 
Does anybody know what the differences are between these two  heads? I  have 
looked at the drawings but have not been able to identify any significant  
differences. Can anybody  help? Why would Chevrolet have drawings for two  
different heads and WHAT IS DIFFERENT BETWEEN THEM?
Thanks in advance,
Regards,
Bob Helt
**************Get the Moviefone Toolbar. Showtimes, theaters, movie news & 
more!(http://pr.atwola.com/promoclk/100000075x1212774565x1200812037/aol?redir=htt
p://toolbar.aol.com/moviefone/download.html?ncid=emlcntusdown00000001)