Just got a note from Jim Carter advising that they have developed a manifold preheater setup that works around problems that many of us have had for a long time. Most try to use the coolant to pre-heat the intake but this uses exhaust gases to do it which to me makes a lot more sense.

Here's what I got in the mail:
Fenton Header Upgrade for GMC Engines (and you Chebby guys too!)

http://www.oldgmctrucks.com