Terrific engine, Dan. Many aircraft had bronze or brass exhaust piping at that time.
The left-handed exhaust collectors are not at all noticeable - unlike the backwards engine cowlings I once produced:
http://www.papermodelers.com/forum/15767-post234.html (over the ensuing nine years, a very funny comment by Ron Spencer has disappeared and a few words dropped out of my post. Last line, graph 2 should read "I don't think I can
explain THAT as battle damage.")
Anyway, your Spider and its engine look just grand.
Don
Don