Joejoe,
Another place you might look is at Carroll Shelby Ent. I saw that their cooling systems were fabbed with mandrel bent pipe and I eventually got them to respond (they aren't very responsive to folks that just want to buy parts). I can't remember what the cost was for the top 90 degree tube but was similar in price to the Woolf products previously mentioned.
http://www.carrollshelbyent.com/engine_index.cfm