Spitfire Mk IV Exhaust Manifold

[Chris and Karen Prugh <prubrew@ix.netcom.com>]

Does anyone know the correct part # for an exhaust manifold, no smog fittings, 
from a late 71 Mark IV Spitfire?  How about a source to purchase new? (old 
stock)  I have been using all new parts, except this "new" O/D tranny, in all 
my replacement projects, and would rather go that route than wrecking yard 
hunting.  Never noticed it before but there are two cracks in the down tubes, 
cyl. one and four.  Anyone see this before?  Possible cause?

Thanks again for the input