No I do not, I wish I did. The description I have is high Si Mo ductile iron but I see Matweb (thanks) has several alloys of that description. I'll look at their CTEs and that will at least get me in the ball park.
I am looking for a CTE for a material that is referred to as 'high Si Mo cast iron' and some refer to it as 'cast steel' though that may be a misnomer. This is a casting alloy commonly used to cast modern exhaust manifolds for gas and diesel engines. For example this is reportedly the casting...